Simple LED flasher circuit can be built using transistor and integrated circuit (IC). LED flasher is very exciting to be built because the LED turns on and off according to a specific time interval (lash rate). With a minimal number of components used to answer questions about the limiting current and the interval of time to blink.

LED flasher also consumes very little power to save battery power, because it usually consists of only a few transistors, electronic capacitors, and resistors. Flash rate control and limit the current to the LED can be done by replacing the resistor values ​​are used. LED current to a value ranging from 10-20 mA depending on LED color is used. Flash rate should be more interesting to follow its computation time of 1 second. You can also connect multiple LEDs in series.

LED Flasher Circuit Diagram

Below are the circuits of the 2 LED flasher using a 12V DC battery power. It’s just not available in the form of PCB to be easy to be assembled. However, it’s also good to be assembled on a perforated blank PCB.

12V LED Flasher Circuit with Transistor

This LED flasher circuit will flash at one-second intervals using two pieces 3V LED blue or white. The workings of this circuit is based on an analog filip-flop circuit of a battery voltage of 12V. Alternatively use a 2.2K resistor instead of the 1K resistor, when using a yellow or green LED. 100K fixed resistor can be changed with the kind of potentiometer, which would occur should blink rate faster or slower.

12V LED Flasher Circuit with Transistor

LED Flasher Circuit with 555 IC

The simple LED flasher below was built using a common IC 555. Square wave output is generated from an oscillator, which is configured in astable mode. At the output (pin 3) connected with two pieces of LED, which lights up in such a way and off alternately. When LED1 is on, the LED2 is off.

LED Flashing Circuit with 555 IC

This LED circuit operate using battery power 5-12V DC. In the circuit, the 10uF capacitor charged exponentially through two 10K resistors and potentiometers 100K. How it works is based on standard operating flasher timer 555, wherein when the 10uF capacitor has charge roughly 2/3 input voltage (VCC). 1/3 VCC will be discharged through the resistor 10K and 100K potentiometer on pin 7. The flash rate can be changed by varying the resistance value of the potentiometer.

Above are few examples of LED flasher is built using transistor and IC. The circuit diagram above would be useful for the beginner to create deeper into the LED flasher circuit.

See also: Smoke Detector Circuit – Water Level Indicator

Here is an optical door alarm circuit is easy to build and can be used in a variety of alarm applications. The compact alarm can also be used on some other equipment in addition to protecting the windows and doors (as a burglar alarm). It consists of a sender LED and a phototransistor receiver.

The door alarm has an easy way of working with just a block or release the block on the path between the infrared LED and phototransistor. When blocked, there is no output anything, and vice versa when the block is open, the output goes high and turn on the sound of the buzzer.

Door Alarm Circuit Diagram

The Optical door alarm circuit consists of two 555 timer IC. The first IC serves as RC oscillator that drives the infrared LED at a frequency on a combination of value and 1K resistor and 4.7uF capacitor. 220 Ohm resistor serves as a current limiter that goes into LED. At the receiver, an IC 555 timer configured as a monostable oscillator to detect the incoming pulses at specific frequencies. When the frequency is not detected, the alarm sounds. Operation of the alarm circuit voltage is 5V to 12V DC, and a single 9V battery can be used for this purpose.

Door Alarm Circuit Diagram

The phototransistor type used in this circuit is the type MRD300 from Motorola is a 50mA / 250mW NPN phototransistor. Equivalent units that can be used to include TIL81, MTD6040, BPW14, L14G2, OP804, BPX43-3, also BPW40. In fact, each phototransistor can be used, and of course may vary according to a system response.

This simple security alarm circuit can be applied to places where possible. It may be useful for educational purposes for those who try to understand the workings of a simple door alarm circuit.

See also: Smoke Detector Circuit – Digital Thermometer Circuit

This simple FM transmitter circuit was built using a transistor with a transmission distance of about 300m around your home. It’s very easy to be constructed in which only consists of the mike audio modulation, and FM oscillator that operate at the base frequency of 100 MHz.

The FM transmitter is very likely built by a novice who wants a chance to experiment with frequency. Although it only has a very low output power of about 1-5 mW, but has a useful range. It’s also useful for sending audio information for a particular application.

Simple FM Transmitter Circuit Diagram

For good results should be assembled circuit on a single sided PCB. This FM transmitter can be operated using battery voltage 3 – 6V. Use a wire antenna is considered sufficient to emit a signal, but you should use a length of wire about a quarter wavelength.

Simple FM Transmitter Circuit Diagram

Tips for getting a steady signal, cut component leads as short as possible. After the audio modulator assembled properly proceeds to the oscillator and also serves as the final. Determination of the frequency is determined by a combination of LC on the transistor collector. Rotate the trimer capacitors to obtain the desired frequency signal on the receiver, or to stretch the spacing of the coil windings L.

You can use any type other than type transistor VHF transistor in the schematic diagram. Most parts of the RF transistor VHF FM receiver can be used for this. Use the type of NPO capacitors when needed, especially for the LC network.

I think it’s very easy to do your experiment, please proceed to the frequency of the FM broadcast frequency band. Not recommended for strengthening the transmission power, because it will cause interference with other frequencies, and this may violate any applicable laws in your state.

These circuits may be useful for your RF applications, but it can be developed further because it is just a simple FM transmitter circuit.

See also: Smoke Detector Circuit – Light Sensor Circuit

There are several ways to designing a 5V power supply circuit, including through AC to DC power supply using a transformer (linear power supply) or without transformer (switch mode) and using a DC to DC converter. A regulated DC power supply can be easily constructed using an IC LM7805.

In certain situations where AC power is unavailable or in mobile conditions can, typically used a DC-DC converter. And or as specified as a requirement to be met or followed-related waveforms, input and output voltages. For example, an isolated DC to DC converter required for data communication applications.

Simple 5V Power Supply Circuit

Build a simple 5v power supply circuit for power up to 1 Ampere, it can be done very easily. LM7805 is the right choice if you want a fixed voltage 5V. Under conditions where the required load currents up to 3A, it can be done easily modified by adding an NPN transistor such as 2N2955 or TIP2955.

High Current 5V Power Supply Circuit

If you read more about the datasheet or application notes of the type of voltage regulator IC 78/79xx series, so much simpler design creations that you can do. Pictured above is a circuit from the Fairchild LM7812 datasheet.

50W Isolated 48V DC to 5V DC Converter

Here is a 5v DC power supply circuit using a buck converter topology. The power supply is a high-frequency forward converter that provides regulated 5V output with 10A load current. Thiis Power supply design offers higher power density and high efficiency of a flyback converter. Although the first-order flyback topology schematics tend to look simpler.

48V DC to 5V DC Converter Circuit

The primary-side control circuit is based on the MAX5003. The MAX5003 represents the next generation of power-supply controllers that integrate many functions that are necessary for the design of telecom power supplies. For high efficiency, output circuit uses a low forward drop and dual Schootky diode. For these applications simply use the diode 20A with a 40V reverse breakdown. Information regarding the information circuit diagram and PCB layout, please download the application note of this IC. Download AN819 MAX5003.

Thus, the above are some examples of simple applications using the IC that can be used as a reference for building a 5V power supply circuit.

See also: Metal Detector Circuit – Digital Thermometer Circuit

A long range FM transmitter circuit below can be an option, especially for the beginner hobbyist FM transmitter. They usually begin to assemble an FM bug with approximately 100 mW of power, which only emit a signal around the house. With a little experimenting in building this transmitter will deliver about 5 watts of output power. Which of course will provide a range of the transmit signal farther than an FM bug.

This FM transmitter was built using a power transistor MRF237 final amplifier driven a buffer amplifier 2N4427 or 2N3866. An FET oscillator using a 2N4416 transistor to provide a stable output frequency of the FM broadcast band 88-108 MHz.

Audio modulation of the transmitter using a varactor diode (capacitive diode) MV2113, where the input sensitivity can be adjusted using a potentiometer 100K to give a clearer audio and clean. Limiting deviation is the 75us audio through a combination of R2C1.

Long Range FM Transmitter Circuit

In the long range FM transmitter circuit diagram, you can find the values ​​of the components used. A suggestion for construction is that you can build the circuit blocks per step starting from the oscillator, buffer, and then final. On the oscillator, the configuration of L1 has 6 turns and tapped at 2.5 turns. You can experiment by turning the output frequency of the capacitor trimmer R5, or even for higher frequencies up to 150 MHz.

Long Range FM Transmitter Circuit Diagram

Once you have established a working frequency of the oscillator in the range 88-108 MHz, you can further build up the buffer that is at or 2n3866 2N4427 transistor. You can set the buffered output power is up to several hundred mW through a C9/C10 (R6 as a dummy load), where the output power level is used to drive the final amplifier. Of course in the output power of this tune you have to use a VHF power / SWR meter.

The next step is to complete the entire circuit in the final. Tuning is done using the C11/C12. Use of a dummy antenna load on the power / SWR meter to determine your maximum output power up to 5W. Then you can adjust the output impedance of the antenna.

To assemble the entire circuit can use the PCB upside down, so that a better grounding. You can create barriers to meeting the component lead and manage in such a way. Keep the component leads cut short as necessary. Alternatively, you can make a PCB, and then assemble the components.

Use a 12V regulated DC power supply, so that the transmitter signal is clean and free of noise. Good luck and happy experimenting with a long range FM transmitter.

See also: Metal Detector Circuit – Light Sensor Circuit

DC Power supply circuit is a device needed to run an electronic application with a fixed output voltage or variable. Power supply voltages are used in accordance with the operation of the relevant application. This means that a power supply with 12V DC output voltage is used for applications with input voltage of 12V DC only. Even advisable to use the power-supply load current in accordance with the current application.

In this article will explain the two types of DC power supply associated with the output voltage, ie fixed and variable. The benefit of a fixed voltage power supply is not necessary to change the output voltage due to be fixed. You can just use the appropriate application of these voltages. Usually the power supply has enough current loads is stable because it is only used on a single load on the voltage.

A variable DC power supply circuit is more flexible in the use of a variety of DC applications during the application of load current is within the specifications of the load current that can be served by the power supply. The benefit is you can select the desired output voltage DC applications appropriate, and monitored on a voltmeter display. Furthermore, you can monitor any changes to the current burden on the output voltage range that you choose.

The following DC power supply circuit is a linear power supply which is used a step-down AC transformer. The AC to DC power supply circuit was built using LM317 and LM337 for the two types of power supply as described above, namely fixed and variable DC power supply.

12V DC Power Supply Circuit

In the circuit diagram below is a fixed DC power supply circuit using the LM317. The output voltage formula for R2 and R1 ratio as attached to the diagram, namely Vout = 1.25V (1 + R2/R1). On the power supply circuit diagram for Vout = 12V (11.99), R1 = 220 Ohm is used, and R2 = 1890 Ohm. You can do this as for some other Vout, including changing the value of R1. (see LM317 datasheet pdf from the manufacturer).

LM317 Fixed DC Power Supply Circuit

Variable DC Power Supply Circuit

In the circuit diagram below fixed voltage output changed to be variable by replacing R2 with potentiometer 5K. Output voltage range will be 1.25-30V DC. It would be very easy for us to experiment to add a voltmeter in the circuit to demonstrate the value of the output voltage.

LM317 Variable DC Power Supply Circuit

For the purposes of increasing the output current is greater, may be worth a PNP transistor is desired, such as the 2N2955, and or replace the family of the LM317, like LM338. This is a simple example and can develop it further for LM317 DC power supply circuit.

See also: Metal Detector Circuit – Smoke Detector Circuit

Temperature Sensor Circuit is a key element required at a temperature sensing. In the process control environment, the temperature is a phenomenon of the most widely measured so that the required precision and high precision in order to represent actual environmental conditions. Some commonly used temperature sensor for sensing the absolute temperature and changes in temperature, such as thermistors, thermocouples (diode), silicon-based integrated and resistance temperature detectors (RTDs).

In a temperature sensor circuit design, there is no precise temperature sensor for all applications. The thermocouple’s wide temperature range is unrivaled as is the excellent linearity of the RTD and the accuracy of the thermistor. The silicon sensor is easy to implement and install in a circuit.

PT 100 RTD Temperature Sensor Circuit

Each of these sensor technologies cater to specific temperature ranges and environmental conditions. The sensor’s temperature range, ruggedness, and sensitivity are just a few characteristics are used to determine That whether or not the device will satisfy the requirements of the application. See Microchip AN679, Temperature Sensing Technologies for reference of the temperature sensor circuit design.

Temperature Sensor Circuit Diagram

Too many sensor circuits that you can use for your own application. However, this time something interesting if a little understanding about the platinum RTD sensor to build a precision temperature sensor. The circuit diagram of temperature sensor below will further increase the knowledge of the temperature sensor design

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RTD Temperature Sensor Circuit

Here is a precision temperature sensor circuit taken from Microchip, AN687. This circuit uses a sensor RTD temperature-sensitive element to measure temperatures from -200 ° C to 600 ° C. An operational amplifier is used to zero wire resistance error, and to gain the signal and interference filter possible alias. A 12-bit MCP3201 converter converts the voltage across the RTD to digital code for the PIC12C508.

Download RTD Temperature Sensor Circuit

See also: IR Sensor Circuit - Light Sensor Circuit

Battery charging circuit is a circuit device used to input electrical energy to a rechargeable battery, or some other electrical cells, which have different current levels. The source of this energy filling in the form of DC current from various sources, e.g. from a solar cell known as the solar battery charging, from the car as a car battery charging, and other DC power supply. So in this case a battery charger is a DC to DC power supply.

A battery charger or a battery charging circuit will conduct an electric current charging by pushing an electric current through it. Charging circuit has a variety of different charge currents depending on the type of rechargeable battery. Because of this then produced various types of the battery charger. For example, a battery charger that comes from car battery power you have different types, if the need to recharge your laptop and cell phone batteries. This is because there is a difference between the current and voltage of 19V to 3.6V at a laptop and cell phone.

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Here is some simple battery charging circuit schematic, which is useful if you intend to build rather than buy. Alternatively, for simply learning how to make a battery charger according to the need for several types of rechargeable batteries such as Lead-Acid batteries, NiMH, Lithium, or 12V battery. Features accompanying the charging circuit is crucial usually disconnected automatically when fully charged, has a charging indicator circuit, and has a fast charging time.

Solar Battery Charging Circuit

This simple battery charging circuit using a typical solar module comprising eight series connected solar cells. Nominal voltage of the module is determined by the number of battery cells to be charged. When active solar panels supply about 140-200mA or more at 8 times the 0.45 V = 3.6 V (depending on the solar panel is used). Connect two diodes in forward bias (cathode connected to ground) when the diode zener value not found. [more]

Solar Battery Charging Circuit

Laptop Battery Charging Circuit

This charging circuit is a switching power supply that is specifically designed as a universal laptop charger, a 20V DC output voltage with a maximum current load 3A. For PCB and parts list visit Universal Laptop Charger.

Universal Laptop Battery Charging Circuit

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Lead Acid Battery Charging Circuit

Here is a Lead-Acid and NiMH battery charging circuit schematic. For more information visit Lead-Acid Battery Charger and NiMH Charger Circuit.

12V Lead Acid Battery Charging Circuit

Battery charger so a few examples that might be useful for you build it, or at least it becomes a reference when you need it in the future related to the battery charging circuit.

See also: IR Sensor Circuit – Smoke Detector Circuit

Ultrasonic level transmitter is a transmitter that is used to convey data information related to the measurement of liquid level and / or solids in an industry to the recipient. Level measurement process uses ultrasonic frequencies, frequencies that above the frequency of 20 KHz, which is usually located in the range of 40-200 KHz.

The use of the ultrasonic level transmitter apart in the industry for the measurement of hot or boiling liquid level and the nature of corrosion is the use for household purposes, for example, for measuring the water level in the tank. So it does not require you to crawl over the tank to check the water level in the tank.

Flowline EchoSpan Ultrasonic Level Transmitter

Principle of Ultrasonic Level Transmitter

Basically an ultrasonic level transmitter has a sensor that has a transducer (ultrasonic transmitter and receiver in one package). Transducer is radiating pulses and sends a signal to / from the object to be measured using ultrasonic sound waves as radar that uses radio waves. When the ultrasonic pulse signal is targeted towards the object, which is reflected from objects and echo back to the sender. Travel time calculated by the ultrasonic pulse, and distance of objects found.

An ultrasonic level transmitter mounted on the top of the tank remains filled with fluid. Ultrasonic pulse signal sent from the transmitter, and is reflected back to the sensor. Traveling time of ultrasonic pulses from the sensor to the target and re-calculated. The basic reference used is the speed of sound waves in the air so that the final measurement units can be specified in meter, feet, or inch

Advantages and Limitations of Ultrasonic Level Transmitter

The advantage of the ultrasonic level transmitter is done without physical contact with the object and has no moving parts. The accuracy of the readings remained unaffected even after a chemical change that is safe at the influence of heat and chemical ingredients that are harmful. This is why the ultrasonic level transmitter is the best level measurement equipment with acceptable quality. This equipment should not be used on objects that absorb sound, and is unsuitable for tanks with a high density moisture and too much smoke.

Some examples of the ultrasonic level sensor circuit, which does not include long-distance transmission (4-20mA transmitter). This description may be useful to understand a little about the ultrasonic level transmitter.

See also: IR Sensor Circuit – Metal Detector Circuit

Burglar alarm circuit is a circuit designed to detect the presence of a site or building from unauthorized access that could be as a thief or intruder. The circuit can be a control panel, an array of sensors, interconnects, and warning systems.

Burglar alarm circuit can be a part of an alarm system that also includes fire protection therein. An intrusion alarm may be part of closed-circuit television (CCTV) surveillance systems in which all the intruder activity is recorded automatically, or can be an interface for access control systems to electronically locked doors. Or even systems ranging from small to complex, self-contained noisemakers, multizoned systems with color-coded computer monitor outputs.

Monitoring windows and door contacts aimed at monitoring the intruders by using sensor technology in the form of electrical or magnetic fields, ultrasonic, vibration PIR motion detectors, and microwave. A control panel that provides power sensor is connected directly or wirelessly to the rest of the array sensor circuit or burglar alarm circuit.

Described above is a review to be considered in designing a complete Burglar Alarm system and integrated. However, wherever a Burglar alarm fitted in your car, including, the ultimate goal is for protection against theft or property damage. Even a good Burglar alarm is not always seen in its sophistication, but to what extent a system that is minimally effective and capable of preventing the theft.

Here is some simple burglar alarm circuit, which may be useful for you to prevent theft activity. Because maybe it will happen to your home, or you need an alarm system at least a fairly effective.

Infrared Burglar Alarm Circuit

This is a burglar alarm circuit that uses the power of invisibility of the IR light beam. Just Break The Beam! This kit includes the infrared transmitter, and receiver operates on standard 9VDC batteries. It’s a highly efficient intruder alarm and free from problems during power failures.

Infrared Burglar Alarm Circuit Board

The infrared transmitter board that generates a high power and focused beam of invisible light that covers up to 13 feet! The matching receiver features a high-sensitivity IR receiver picks up that beam that and when broken, sounds a built-in 85dB audible alarm and lights an LED. projects.

Car Burglar Alarm Circuit

This burglar alarm kit is not only used for cars as well for the home, room and closet. It’s very easy to build a simple way of working. When someone opens the door or tries to remove the radio, an alarm is activated and the car horn will sound. You can see the burglar alarm circuit diagram here.

Car Burglar Alarm Circuit Kit

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Installation of burglar alarms can reduce the fear of theft as long as it is installed in the right place, not on how the price you bought it. Although the above circuit’s only simple burglar alarm circuit.

See also: Crystal Oscillator Datasheet – Smoke Detector Circuit

Ultrasonic level sensor is one approach commonly used of the various types of measurement-level offered in the market today. However, there is some other very common method in the measurement of level, such as RF Capacitance, Radar, Conductance (conductivity), and Hydrostatic Head (tank gauging). Which method you choose, you need to understand the underlying theory and how each one works.

Level measurement using radio frequencies (RF) is a set of different configurations of the electrical characteristics of a capacitor. All types of this type use the frequency range from 30 KHz to 1MHz. An ultrasonic level sensor consists of a transmitter and receiver, which operate using sound waves to determine the fluid level. As for the type of ultrasonic level sensor (transmitter / receiver) using a range of 20-200 KHz, and the sonic type is a frequency of 10 KHz.

The working principle of an ultrasonic level sensor is to transmit sound waves from an ultrasonic transmitter to the surface of the liquid level to be measured. A piezoelectric crystal inside the transducer converts electrical pulses into sound energy moves in waves at a frequency that was established and at a constant speed in a particular medium. Echoes that reach the liquid surface will be reflected and returned and received by the transducer of an ultrasonic receiver.

The time taken by sound waves to return is directly proportional to the distance between the sensor and the piezoelectric material in the tank. Based on the measured time by the sensor is then used as the information to calculate the level of liquid in the tank.

Velocity of sound waves can sometimes be affected due to the proper temperature variation compensation should be provided in the sensor design. In general, the media on the surface of the fluid is air. However, one can use a blanket of nitrogen or steam as well.

Ultrasonic Level Sensor Transducer

Ultrasonic Level Sensor Installation

In the non-contact design, the ultrasonic level sensor is located above the tank in such a way that sends sound waves in the form of bursts in the direction of the liquid in the tank down to below the measurement level. Immediately, after the sound wave hits the surface of the liquid is directed, the echo will be reflected and returned to the sensor.

Ultrasonic Level Sensor Installation

Ultrasonic Level Sensor Circuit

Very varied types of ultrasonic fluid sensor current and with different methods of approach led to many design variations associated with the ultrasonic level sensor. Here are some examples of such circuits that have different features or optional.

Ultrasonic Level-Sensor Circuit with LED Display

The following circuit is an ultrasonic level sensor comprising an ultrasonic transmitter and receiver circuit. This circuit was built using IC 555 and a transistor amplifier cascade as a high-gain amplifier in the receiver. Ultrasonic UMC40 transducer using a type-T (transmitter) and UMC40-R (Receiver)

Ultrasonic Liquid Level Indicator Circuit

The workings of the ultrasonic liquid level indicator circuit is when the liquid level is closing to the receiver’s head, the voltage meter’s deflection angle would be increasing. The closer to the liquid level, the bigger the corresponding deflection angle would be. Because the ultrasonic has the feature that it would not be effected by the liquid’s concentration and electric conductivity, so this circuit would be better and have higher accuracy than general contacting liquid level display circuit. Seekic.com

Such a glimpse of the level measurement concerning the workings, installation, and the circuit, you might be interested with it. Many other online resources that it can be used as a reference for learning more about the ultrasonic level sensor.

See also: Crystal Oscillator Datasheet – Metal Detector Circuit

Many variations of the DC power supply schematic that we encountered when we’re surfing on the internet about this phrase . Starting from a simple schematic to the complex, from unregulated (stabilized) to regulated (unstabilized) voltage, from fixed to variable (adjustable) voltage. The extent to which you want to build it depending on how far you want to influence the specification of an application that will run with it. But this certainly is not an issue is not being used for applications with special specification.

In general, things must be considered in selecting a DC power supply schematic is the extent to which the voltage drop and voltage ripple level. Because of these factors greatly affect the application of audio and RF circuit, which is marked by humming or vibrating noise at the output of the application.. Here are some examples of the power supply circuit which can be practiced with ease.

12V DC Power Supply Schematic

This is a regulated DC power supply and simple to use regulator IC 7812. The regulated and unregulated distinction of a DC power supply t is the use of voltage regulator or not. The use of a diode rectifier is useful to convert AC current into DC current. The 12V power supply circuit can be used for applications with a maximum DC current of 1 amp.

12V Power Supply Schematic

For the purposes of applications which require dual polarity of the voltage amplifier circuit such as the use of the bipolar power supply needed. This circuit is also known as symmetrical power supply. By harnessing the full-wave bridge rectifier in the circuit above, then added a 7912 IC to the output voltage with negative polarity. This approach is used in a transformer with a center tap (CT).

12V Bipolar Power Supply Schematic

Variable Power Supply Schematic

The schematic of DC power supply above is a power-supply circuit with a fixed output voltage using a voltage regulator IC 78xx/79xx series. In the following schematic, the LM317 regulator IC is used with the aim of changing the output voltage over a voltage range with output current up to 1.5A. This Power supply is usually referred to as adjustable or variable power supply.

LM317 Variable Power Supply Schematic

15V Switching Power Supply Schematic

The schematic of power supply above is based on the use of transformers known as the linear power supply. See here for a transformerless power supply. However, here is a switching power supply using monolithic IC high-voltage power switching regulator MC33374 from Motorola. The power supply is capable of delivering a maximum output of 90W, with 6A current at 15V DC output voltage. Download Application Note.

ATX Power Supply Schematic

ATX power supply is one type of switching power supply that we know, which is widely used on PC Computer. By understanding how it works can be through a schematic. Here’s one example of the schematic and for more you can visit this site ATX power supply schematic.

300W ATX Power Supply Schematic

Based on a sample schematic of power supply described above are expected to provide a tiny fraction of enlightenment for those who want to understand it further. Theoretical knowledge can help in understanding about the power supply schematic.

See also: Crystal Oscillator Datasheet – IR Sensor Circuit

A fire alarm circuit is a circuit that is used to warn people in case of fire to play an alarm sound and / or flashing warning lights. A simple fire alarm circuit has a sub-circuit, including a heat detector, flame detector, smoke detector and other detectors, such as gas leak detector and the ionization detector.

Whole of the above circuits are integrated will detect the possible cause of a fire and then deliver the signs to the rescue of people who may be performed. The importance of a fire alarm circuit for the safety of the people it is necessary to fire prevention efforts. Real effort is supposed to do is to install a sub-circuit at various locations to observe the factors most likely cause. As an example of a gas leak detector installed in the kitchen stove.

Cadmium Sulfide Flame Sensor

In this article, there are some circuits that are part of a complete fire alarm circuit. However, it does not provide how a fire alarm circuit wiring is installed, only limited mounting each detector was individually. So there are no fire alarm circuit styles.

Fire Alarm Circuit Diagram

The fire alarm circuit is a heat detector which uses a Thermistor resistance will decrease as the temperature increases, and vice versa. Thermistor specification used is approximately 10K Ohm, when the temperature rises above 100° C will decrease some of the Ohm resistance.

Simple Fire Alarm Circuit with Thermistor

Detector and alarm circuit diagram below can be used to support your efforts to create a fire alarm circuit design of your own system. Here is a gas leak detector on the stove with sound and light alarm circuit.

Gas-Stove Fire Alarm Sound & Light Circuit

Heat Detector Circuit

This heat detector circuit is built using the LM35 temperature sensor. This overheat detector can provide a linear output accurately and directly proportional to the mV, in the zero to 155 degrees C temperature. It develops an output voltage of 10 mV/K change in measured temperature and has very low self heating in still air. The LM35 designed to draw a minimal current of its own. This circuit can be used as part of a smoke detector.

LM35 Overheat Detector Circuit

Smoke Detector Circuit

The following smoke detector circuit is simple and compact enough to be built using an IC CS235 from Cherry Semiconductor. The light source uses a pulsed infrared LED and a silicon diode, and a pair of detectors are used together.

Photoelectric Smoke Detector Circuit Diagram

Flame Detector Circuit

The following circuit is a flame detector using LM10 from National Semiconductor Application Note. It can directly drive digital circuitry. The platinum-rhodium thermocouple gives an 8 mV output at 800 ° C. This threshold is established by connecting the balance to the reference output pin. See circuit diagram of the Flame detector.

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Hopefully, it can be seen from the above description of the various sub-circuits of a fire alarm. And the circuit above is only intended for educational use only. The most important is the presence of minimal effort should be done by installing a detector circuit that may be needed most of the fire alarm circuit.

See also: Quartz Crystal Oscillator – Metal Detector Circuit

As you already know, there are several ways to measure AC and DC is by a meter and a resistor. However, these methods are not fully insulated with applications that run and have a high security risk. This will be very different when using a hall effect current sensor.

The use of a hall effect current sensor transducer for the measurement of AC / DC current will minimize security problems. The transducer really will be isolated from high voltage electrical system that eliminates the risk to the monitoring equipment.

CSLA2CD Hall Effect Current Sensor Transducer

Magnetic field around the wire will be detected by current sensor that is fully insulated and there is no electrical contact between the sensor and wire. This is a very nice benefit, when compared with a precision shunt resistor current monitoring. So by using a hall effect current sensor transducer, temperature heat will escape the problem of heat dissipation from the wire. Even when you measure the current over 30 amps though.

If the signal is too weak, or you do not get the resolution you want, you can just loop the wire through the clamp at this time as much as you want to double, triple, or quadruple the sensitivity or resolution of your sensor. For example, if your signal is now only .03 Amps, you can loop the wire on the clamp sensor 10x. Then the signal will be an advanced 10X more powerful, and will appear as 0.3 Amps.

The Measurement using the product CSLA2CD Honeywelll, and you can get a AC / DC Hall Effect Current Sensor Transducer here.

Hall Effect Current Sensor – Wiring Diagram

You can use a hall effect current sensor transducer to measure the electric current in various applications such as wind power, hydro, and solar. The following wiring diagram of a hall effect current sensor transducer in solar power applications.

Hall Effect Current Sensor - Wiring Diagram

In the diagram above to use step-down regulator 7808 to provide a stable DC voltage to the hall effect current sensor circuit, the input voltage from a 12V DC wall adapter. This is very important output, because the sensor is only ~ 0032 volts per Amp That it measures, so if the voltage you are supplying the CLSA2CD is noisy; your data will get lost in the noise. The ground is shared throughout the circuit.

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Hopefully, this information is useful in the installation of electrical current measurements using a hall effect current sensor.

See also: Quartz Crystal Oscillator – IR Sensor Circuit

A digital voltmeter circuit is a circuit used to measure the voltage of electrical devices and circuits. For the measurement probes are typically equipped with black and red in negative and positive polarity. The measurement results are shown in figures showing the amount of voltage that is being read.

The accuracy must be greater than a digital voltmeter circuit compared with an analog voltmeter. The accuracy or resolution is usually displayed in the form of the number of decimal places. This can be taken into consideration if you want to determine the type of display you want to use, whether it be LCD or LED only.

ICL7107 Digital Voltmeter Circuit Diagram

As follows is a digital DC voltmeter circuit, which is good for your DIY home project. This digital voltmeter circuit has a resolution of one decimal place for measuring the voltage from 0.1V to 199. 9V. For it is only required four pieces of seven segments LED display.

ICL7107 Digital Voltmeter Circuit

Parts List:

R1 = 8K2 R1 = 8K2
R2 = 47K / 470K R2 = 47k / 470K
R3 = 100K R3 = 100K
R4 = 2K R4 = 2K
R5, R6 = 47K R5, R6 = 47k
R7 = 0R / 4K7 R7 = 0R / 4K7
R8 = 560R R8 = 560R
C1,C5, C6, C8, C9 = 100n C1, C5, C6, C8, C9 = 100n
C2 = 470n / 47n C2 = 470n / 47n
C3 = 220n C3 = 220n
C4 = 100p C4 = 100p
C7 = 10-22u C7 = 10-22U
D1, D2 = 1N4148 D1, D2 = 1N4148
IC1 = ICL7107 IC1 = ICL7107
IC2 = NE555 IC2 = NE555
OPTO = CA 10 pin FTA = CA 10 pin

Digital voltmeter circuit based on single ICL7107 chip and can be mounted on a small PCB board 3cm x 7cm. The use of 7805 5V voltage regulator is highly recommended to prevent damage to the ICL7107. Source: ICL7107 Digital LED Voltmeter.

PIC12F683 Digital Voltmeter Circuit

Here is a simple digital voltmeter circuit using a PIC12F683 microcontroller. The voltage measurement range is 0-20V DC, and the results will be displayed on an LCD display.

PIC12F683 Digital Voltmeter Circuit

Source code is available if you want to build one. Digital voltmeter circuit of this project has not yet issued a PCB for it. One thing is certain; the PCB from the digital voltmeter would be very compact and small. [link]

Similarly, the resources that are helpful to build a digital voltmeter You can visit the link above, if you want to know more how to make it based on the digital voltmeter circuit.

See also: Quartz Crystal Oscillator – Crystal Oscillator Datasheet

FM transmitter has become a popular hobby these days. From a simple FM transmitter to the digital FM transmitter circuit, has gained knowledge can be built with PIC programming. So an FM transmitter made ​​compact and controlled by a microcontroller.

A simple FM transmitter circuit can be used as a wireless microphone (FM bugs). And can also be used as a medium for delivering audio around the home environment or a small FM transmitter station. This became a fun hobby for the RF hobby, can make or assemble an FM transmitter.

Below is a stereo FM transmitter circuit diagram where you can experiment with it. The FM transmitter have been equipped with a stereo encoder in order to deliver the second channel audio sources. However, most important is its frequency stability because it uses a phase locked loop (PLL) as an oscillator or known as PLL synthesized FM transmitter. Ths transmitter can works in the 88-108 MHz FM broadcast band.

FM Transmitter Circuit Diagram

For educational purposes, you can explore on this FM transmitter circuit. The heart of the PLL is an IC MC145151-2 single modulus and a frequency divider IC 74F160. Here is the block diagram and  the transmitter circuit schematic.

MPX96 FM Transmitter Circuit Board

MPX96 PLL FM Transmitter Circuit

Determination of the frequency of the oscillator follows the calculation of a binary number and pin set at 11-20, 24 of the IC MC145151-2 which can be switched on / off. Stereo encoder uses a balance modulator IC MC1496. This transmitter has a transmission range of about 50-200 feet using 11-15V from a regulated DC power supply.

Here is a link if you’re interested to explore how to make a PLL FM transmitter. You can follow the following link PLL FM transmitter. Happy studying and experimenting transmitter of a good FM transmitter circuit.

See also: Crystal Oscillator Circuit – IR Sensor Circuit

The AM transmitter circuit is designed to work on the broadcast band (530KHz-1700KHz). This is a high quality AM transmitter that is easy to build and adjust. The radio transmitter has a stable output frequency with excellent fidelity, because it is built using the broadcast band crystal.

Other features also complement the AM transmitter circuit is an output meter that allows you to put a reasonable signal level and check the antenna tuning while on the air. A simple audio mixer has been prepared for several audio sources like CD players, MP3 players, and tape recorder. This is the first step towards a low-power AM transmitter professional.

AM Transmitter Block Diagram

Below is an AM transmitter block diagram is simple to understand, the audio from microphone to antenna or aerial. Here is an explanation block diagram of AM transmitter circuit:

AM Transmitter Circuit-Block Diagram

• Audio: an audio block is set regarding processing of audio and voice-related quality of audio. This usually consists of control channels, audio amplifiers, and audio processor (on a commercial press).
• AM Modulator: this block is where the modulation amplitude of the RF carrier from the oscillator does. Audio signal is modulated onto a radio frequency carrier to the modulation stage. By varying the modulation can be (height) the amplitude of the carrier is known as amplitude modulation (AM).
• RF Oscillator: here defined frequency or frequency range in which the transmitter will operate, in order to avoid interference to other frequencies or frequency bands. For commercial purposes, you must have a registered license.
• RF Power: The signal amplitude modulation which has a deviation is permitted will be strengthened in this block. Of the power of reinforcement will be categorized from low to high power. The higher the power is emitted, the more stringent requirements of the RF filter. The next stage of the signal will be emitted through the correctly matched antenna to the entire coverage area.

AM Transmitter Circuit Diagram

Below you will find a simple AM transmitter circuit, near-professional AM transmitter can be built. This transmitter works in the broadcast band uses a crystal oscillator according to the frequency that you want to operate. This transmitter requires a voltage to operate from 15V DC power supply., with a maximum output power of 100mW (legal limit)

High Quality AM Transmitter Circuit

The transmitter is equipped with a mini audio mixer and signal level meter. For more information, how the transmitter is constructed and configured you can download it at the following link AM Transmitter. This is a good transmitter project, especially for beginners who want to build a transmitter of a quality AM transmitter circuit.

See also: Crystal Oscillator Circuit – Crystal Oscillator Datasheet

There are several ways to convert AC voltage into DC voltage. One is using a transformer that has been done so far. Otherwise it is called a transformerless power supply. This method is less commonly used except for the purpose of lower cost power supply itself. Then a safety risk should also be a primary goal, because you are dealing directly with the high-voltage AC power (no transformer), which is very dangerous and deadly. So that in use, power supply must be wrapped or insulated very well for the safety for the user.

Transformerless power supply is not recommended for beginners fatherly. It is more aimed at educational purposes only. It is widely used in micro controller-based applications that are powered from a wall respectacle. For example, the fire alarm can be supported in this way, where a transformer is considered large and expensive, especially if the device is a consumer product.

Transformerless power supply consists of two types, namely resistive and capacitive power supply. Both offer cost and space savings when compared to the transformer based power supply and switch-based power supply. Capacitive power supplies offer energy-efficient solutions, while the resistive power supplies offer increased cost savings.

Transformerless Power Supply Circuit Design

Transformerless power supply works by using a reactance to limit the current and the diode to rectify the voltage. Then the voltage will be regulated by a zener and filtered to disappear from ripple voltage using a large electrolytic capacitor.

Capacitive Transformerless Power Supply Circuit

A clear understanding of how to design a transformerless power supply, you can download the Application Note (AN954) from Microchip. You can understand on a circuit analysis, the benefits and disadvantages of each power supply, and additional considerations, including safety requirements and trade-offs associated with the half-bridge versus full-bridge rectification.

Transformerless Power Supply Calculator

To simplify the design of the power supply, you can visit the following link:

Transformerless Power Supply Calculator

Hopefully, the description above you can make it easier to design a transformerless power supply.

See also: Crystal Oscillator Circuit – Quartz Crystal Oscillator

The question how to make a homemade metal detector, people may come to mind. It may have a metal detector is still a dream for some people. How curious it appears when the beep sounds when the detection of finding something that is still a conjecture. Yes indeed, metal detecting can be a fun hobby.

If you have not been able to buy a metal detector was not wrong to have homemade metal detector plans. Maybe you can buy a DIY metal detector kit, or if maybe you create your own based on clues from various sources from the internet.

A simple homemade metal detector can also work well for metal detecting. In the metal detector, technology refers to the three methods such as Beat Frequency Oscillator (BFO), Pulse Induction (PI), and Very Low Frequency (VLF). Each of these three types of the metal detector has the same function that detects metal or metal content. However, the emphasis is more on the importance of the goal itself, because the world’s industrial metal detector used to detect levels of certain metals contained in a food.

Simple BFO - Homemade Metal Detector

However, our goal is not far, just wanted to make a homemade metal detector even the very simplest of all types of the metal detector, which is a Beat Frequency Oscillator (BFO). However, still quite useful for detecting many applications. And although this one is very simple, it works very well.

How to Make a Homemade Metal Detector

Here’s a site Chemelec: My Simple BFO Metal Detector, where you can learn a lot about how to make a simple metal detector. Here you can find the documentation concerning the circuit diagram, PCB, and how to make the loop coil of the metal detector.

I hope this information is helpful and answer some questions about how to make a homemade metal detector.

See also: Crystal Oscillator – Crystal Oscillator Datasheet

If you are looking for a simple water level indicator circuit, then you are interested to build it, this is the right choice. Only 16 components installed on a compact PCB. Even the water level indicator circuit is already available in a kit which you must assemble. In one complete package comes with a 9V battery and the snap for around $7.

Water level indicator circuit kit involves three pieces of NPN transistor, 10 resistors, three pieces of each color LED red, green, and yellow, and with a single small PCB. You do not need an external DC power supply to operate, it has been available 9V battery snap. Next, you need to assemble and put it in a box to protect from outside conditions. It does not require any special skills to assemble, even very suitable for a beginner.

Water Level Indicator - Kit & Box

Water Level Indicator Circuit Diagram

The water level indicator kit is very simple designed to measure water level in a pool or tank by using LEDs to show the water level. Diagram of the water level indicator circuit as here.

Water Level Indicator Circuit - 3 Level

Explanation of Water Level Indicator Circuit

• One probe goes into the water and is connected to the 9V positive rail through a 100 ohm resister.
• The other 3 probes connect to the base of each transistor through a 390 ohm resistor.
• When the current flows from the probe to the sense contact connected to the base of the transistor, the LED light will turn on.
• The tank water level indicator has 3 inputs, low, medium and high. (yellow, green, red).
• power supply 6-9 V.
• box for product FB03.
• 9V Battery Snap BS-IR.

NOTE:
Probes are not included. Probes can be made up of stainless steel screws connected to wires that run back to your circuit board or just wires in contact with the liquid.

WIRE:
The insulation should be stripped back 1/2″ to expose the conductor, then tin the conductor using appropriate solder.

From the description above is expected to outline the basic workings of a simple water level indicator. You can visit the site to obtain more information on the Water Level Indicator Circuit.

See also: Crystal Oscillator – Quartz Crystal Oscillator

Water level indicator is an electronic circuit that monitors the water level in a tank. The presence of water in the tank can be interpreted through the sensors are placed in the tank, then this information is processed in analogue or digital form to be expressed in the form of a panel of lights and sounds (alarm). So this device is still functioning manual tells us that the water level conditions have been met, and the rest is up to you.

A tank water level indicator should have a relay driver or automatic switch to turn off or turn on the power source of the water pump, is usually called a water level controller. Even a device controller can control the water level more than one tank of water at a particular location automatically. Minimal feature of this device is capable of detecting the lowest and highest water level in the tank.

Although a water level indicator can be added the ability to be a water level controller, but below are a variety of examples to convey water level indicator circuit from various sources. It simply aims to provide information for those of you who are interested to build a water level indicator for your own purposes.In addition to a water level sensor can be used to detect the height of the water being poured into the aquarium.

Water Level Indicator Circuit

Low-Cost Tank Water Level Indicator

Here’s a simple water level indicator circuit that uses five green LEDs in the bargraph display. This LED display will give an indication on how to hold the water supply. More LEDs that light, the higher the water in the tank. A red LED lamp sixth when the tank level drops below a critical threshold.

Water Level Indicator Circuit Board

Design objective of the level indicator circuit is a common part to keep costs as low as possible. In fact, there are no fancy microcontrollers or digital displays used in this project. The purpose is for sure that you do not want to crawl up on top of the tank every time you want to know how much water is present inside it. Source: Silicon Chip

Water Level Indicator with Alarm

Water level indicator provides a visual display which indicates the liquid level with a choice of alarm that sounded at the desired height of water level. Besides being used to monitor the fluid level in the vessel, you can use it in a bath or a cold storage tank. Source: Water Level Alarm

Water Level Alarm

Tank Water Level Controller Project Kit

Forgotten to turn off the tap, leaking washing machines, water level dropping in your aquarium, water in your cellar, etc. Such situations are often the cause of trouble and financial burden. Prevention is better than cure.

Hopefully, this explanation can be useful in building a powerful water level indicator.

See also: Crystal Oscillator – Crystal Oscillator Circuit

The digital thermometer circuit is built, almost all by using the temperature sensor of some form of discrete components, such as a solid-state sensor or a thermistor. It is intended to actually measure the temperature of the environment with emphasis on how a micro controller to interpret the readings into a human-friendly form for the benefit of users.

However, unlike the digital thermometer circuit description of the above, since it allows that a digital thermoneter designed without an external sensor, by using the temperature-sensitive property of the microcontroller itself. This is an Application Note on how to measure the temperature with the PIC16F84A Watchdog Timer. (Leena Chaudhari, Microchip)

Digital Thermometer Circuit Diagram

Here is a circuit diagram of the digital thermometer based on PIC16F84A microcontroller made by Microchip. Thermometer is unlike the classic built digital thermometer that still uses an external sensor. This is a complex solution in the design of the system since it involves only a few external components. The design aims at a low cost applications but provides measurement results with high precision.

PIC16F84A - Digital Thermometer Circuit

The microcontroller of the Digital thermometer circuit uses watchdog timer function to measure temperature. The WDT on all microcontrollers PICmicro has a nominal time-out period of 18 ms. The WDT time-out period varies with temperature, VDD and part-to-part process variations. It’s possible to calculate the temperature with reasonable accuracy using the WDT time-out period without using a separate temperature sensor,

Treatment system in order to interpret the environmental temperature becomes an actual reading is the following:

• Provide a method for Establishing time-out to temperature calibration
• Count the number of WDT time-outs for a given period of time
• Equate the number of time-outs to a temperature

In Application Note, PIC16F84A, you can learn from the design parameters for the digital thermometer available projects, the circuit diagram and source code. For more information about the design, you can visit the following link digital thermometer circuit.

See also: DC DC Converter Circuit – Quartz Crystal Oscillator

Light sensor circuit, such as the name is a circuit that utilizes the light intensity / beam for the other applications do automatically via the relay to switch on / off under certain conditions. Applications such as these and more we encounter in everyday life, such as automatic garden lights, LED lighting / IR LED, light activated alarm, and others.

Light sensor circuit requires a light detector which can be a Light Dependent Resistor (LDR) or Photodiode. The circuit measures the ambient light intensity is called ambient light sensor circuit. Basically, it can simply be a light sensor circuit consists of three parts, namely the ambient light sensor, relay driver, and application design. So it can be concluded that a light sensor circuit is a light sensor switch circuit.

LDR & Photodiode - Light Sensor Circuit

The Light Dependent Resistor (LDR)

Measurement of ambient light level of the light sensor circuit can use the LDR. An LDR (light dependent resistor) is composed of semiconductor material plate with two electrodes on its surface. Resistor value of an LDR is determined or strongly influenced by light.

In the dark or dim light environments, disk material contains free electrons in a relatively very small amount. There are a number of free electrons to flow of electric charge. That is, the material is a poor conductor of electric current, because the very high resistance materials.

In an environment with sufficient light, more electrons can escape from the atoms of a semiconductor material. There are more free electrons that can drain the electric charge. Under these circumstances, the material is a good conductor. Low electrical resistance material. Brighter light on the material, electrons are more available, and the lower the electrical resistance of these materials.

The Photodiode

Photodiode light sensor construction is similar to a conventional diode PN-junction diode except that the outer casing is either transparent or have a clear lens to focus light to a PN junction for increased sensitivity. Intersection will respond to light, especially the longer wavelengths such as red and infrared light than visible light.

Light Sensor Circuit Diagram

Various applications relating to the ambient light sensor can be easily met on the internet, that you can follow the links associated with the light sensor circuit diagram according to the keyword or phrase you are looking for. However, here only to deliver the basic understanding of light sensor.

Simple Light Sensor Circuit

Here below are some examples of applications that measure the ambient light level using the LDR which is used to detect light in the environment. Then the output signal of the circuit is routed to a relay driver to switch the application after it. And is commonly referred to as a light sensor switch circuit.

• Smart Garden Light
• Infrared Illuminator
• Automatic Light Controller

Presumably, there is little understanding of a light detector, especially on how to make a simple light sensor switch. There are many more variations on how to design a light sensor circuit.

See also: DC DC Converter Circuit – Crystal Oscillator Circuit

One of the most important safety devices you can have at home is smoke detector. Smoke detector circuit shall be installed in the bedroom and hallway. In case of fire smoke detectors will provide early warning, and urgent action allow the user if a fire does occur. Besides the cheap price of smoke detectors, you do not need any special skills to install, requires very minimum maintenance, unobtrusive, and no home should be without them.

Before entering the smoke detector circuit, keep in mind that there are two common types of smoke detectors – ionization and photoelectric type. Ionization type smoke detectors can display hazardous radioactive sources in the dual detection chamber. Ionization detector response to the invisible products of combustion. They operate by sensing changes in electrical conductivity in the detection chamber. The advantage of the ionization detector is that the smoke could not be seen by human eyes, but still very visible with ionization detectors.

Photoelectric smoke detector circuit works on a completely different principle. Photoelectric detectors look for the presence of combustion products in the detection chamber. When the density of flammable enough to fill the space visible detection, the detector sounds an alarm condition.

But this topic does not display below ionization smoke detector circuit, only a photoelectric smoke detector circuit for a practical purpose for the hobbyist who are interested.

Smoke Detector Circuit Diagram

The smoke detector circuit is quite simple and compact to be built because it does not involve many components. Smoke detector circuit was constructed using an IC CS235 from Cherry Semiconductor. The light source uses a pulsed infrared LED and a silicon diode, and a pair of detectors are used together. With the addition of several discrete components, you can create a smoke detector is sensitive and reliable. By cascading multiple detector modules, a complete home smoke-detector system can be made.

Photoelectric Smoke Detector Circuit Diagram

The smoke detector circuit uses very little energy. Pulse from the system once every 10 seconds for 20 milliseconds. The second part of the period of 20 ms pulsed, LED and sample to condition the smoke detector. After the first signal is detected, a sample rate increase to a 2-second interval. After three consecutive alarm level samples are accumulated, the logic signal drives the output latch on pin3. This synchronous detection method has very high noise rejection and provides excellent reliability.

The internal latch can sink 100mA, and a low-current relay controlled directly. The CS235 uses a 12V DC supply. The bolt is determined by the current resistor RL shown in smoke detector circuit diagram, and depending on the relay, especially in the system.

The smoke alarm system uses a two-mass-system. A high base is present, is connected to pin 4 and the low mass is connected to the voltage divider at pin 5. The CS235 smoke detector system is easy to build and reliable protection. The smoke detector circuit can be operated from a 12V battery trickled calculated for a 110 V source.

All the resistor values ​​using the 1/4 watt. You can follow the link below to download the CS235 datasheet. It explains an outline for those of you who want to experiment and be creative with the smoke detector circuit.

See also: DC DC Converter Circuit – Crystal Oscillator

The metal detector circuit is an electronic circuit that is specifically designed to detect metal that lies deep in the water or soil. In addition to these objectives are specifically designed for screening or security purpose and to search for mines. Even in the industrial metal detector circuits are used as pharmaceuticals, and food processing, packaging and plastics industry, textiles and chemicals. Metal detector is an important tool to check for metal debris for food to avoid food poisoning.

Various types of metal detectors on the market, basically metal detector circuit consists of three types are adopting technology used as VLF, BFO, and Pulse Induction (PI) technology. A description of the metal detector technology will be described briefly along with metal detector circuit examples as below.

Very Low Frequency (VLF) Metal Detector Circuit

VLF metal detector circuit uses the most common technology. Metal detector consists of a set of two, which is the receiver and transmitter coil. Receiver coil sends an electric current, and creates a magnetic field pressed to the ground continually, and transmitter coil retracts the magnetic field. The magnetic field is produced by reacting to a metal detector in a metal or a conductor that passes over it. Electric current and magnetic field formed around the conductor, when the object is found.

Receiver coils should only be influenced by the conductor and / or a metal object’s magnetic field itself. So that these coils should be protected from the influence of magnetic fields produced by the transmitter coil. Electricity that runs on the receiver coil generates a weak magnetic field when a conductor is closer to the metal detector. In turn coil will amplify and transmit electrical frequencies that have the same frequency with the magnetic field emanating from the metal to make the analysis in the control box. Through this, the VLF metal detector circuit that works on very low frequency (VLF) will be able to determine the difference between the types of metal, the depth of the current position is detected. Here for more information about VLF Metal Detector Circuit.

Pulse Induction (PI) Metal Detector Circuit

On the Pulse Induction (PI) Technology, metal detector circuit have a decent single coil is used on both the receiver and transmitter, although it also allows use of up to 3 coils. Metal detectors can send a short burst and / or pulses of current in the coil that will produce a magnetic field is shorter. The magnetic field generated in each pulse will reverse the polarity and will eventually collapse. Electrical surge can be created and will take place in a very short time. When the magnetic field, pulse and spike collapses, a known current called as reflected pulse will occur and into the coil, it will run. This reflected pulse can only last in seconds.

When a metal or a conductor will get in contact with a metal detector, the pulse is reflected to survive in a longer time. The reason of this is caused by an opposing magnetic field produced by the metal detector. Metal detector is a device that has an integrator circuit which contains a sample that can be monitored closely on each spike. It is to convert the signal, reads and amplifies the signal will change into a direct current. Audio circuit is connected when getting the right amount of electricity will produce tones that indicate the presence of metal objects.

Pulse Induction - Metal Detector Circuit

Source: Pulse Induction Metal Detector – GoldPic 3

Beat Frequency Oscillator (BFO) Metal Detector Circuit

The beat frequency oscillator is like the VLF (very low frequency) that uses two-wire coils. The first coil of the device can be found in the control box, and in the search head lays the second coil. The first coil which can be found in the control box most of the time is smaller compared to the second one in the search head. The two coils, on the other hand, stay connected in the oscillator that sends an out number of thousand electric pulses per second. When the pulse passes through every coil radio waves can be created and the receiver that can be found in the control box collects them all.

After this you will hear clear tones like the radio wave frequency which is created by the receiver. The current of electricity that is moving in the coil in the search head will create a field of the magnet that creates a new field of the magnet around the metallic object as the metal detector passes over the metals. The creation of radio waves from the search head coil is being interfered by the magnetic field created by the metallic objects. This produces a change of tone in the receiver these changes can help in detecting the object in being targeted.

BFO Metal Detector Circuit

Source: How to Make a Metal Detector -  Easy Treasure.
Visit a useful link for BFO Metal Detector Circuit – Bob Data.

Elenco K26 Metal Detector Circuit Kit

So at a glance info about the metal detector circuit but technological developments will continue to develop the tools that help enhance any easier everything in human life. Homemade simple metal detector would help you to know better in a metal detector circuit.

See also: Solar Tracker Circuit – Crystal Oscillator Circuit

IR sensor circuit is a circuit that includes use of electronic devices that emit and / or receive through the detection of radiation to experience some aspects of the environment. Infrared (IR) sensor device normally used to detect the temperature or the heat of an object and also the movement. When the sensor is only intended to measure the level of infrared radiation only, not the other way, then it is usually called a Passive Infrared (PIR) sensor.

Basically, that every object has or emits some form of thermal radiation. Radiation is invisible to our eyes, but usually this is in the infrared spectrum. For this reason, IR sensor circuit is required, which can receive and interpret radiation can be detected in the spectrum.

In an IR sensor circuit, IR motion detector, the detected radiation from a change motion into forward and reach the sensor itself in the middle of the device. This section may consist of more than one individual sensor. Each of them made of pyroelectric material, the material that generates an electrical voltage when heated or cooled.

IR Sensor Circuit - IR Proximity Sensor

Pyroelectric materials are integrated into a small circuit board. They are wired such that when the sensor detects an increase in heat a small portion of the field of view, it will trigger the alarm from the motion detector.

On motion detector applications, most of the IR sensor circuit is equipped with a special kind of lens on the face of the sensor, known as a Fresnel lens. The lens is useful for focusing the light from multiple directions, providing views of the entire sensor area. Some motion detectors are equipped with a small parabolic mirror works the same as Fresnel lenses.

IR Sensor Circuit - Fresnel Lens

An infrared sensor circuit can be thought of as a camera, which briefly a recall how the emerging area of infrared radiation. A sudden change in one area of ​​the field of view, especially the move, will change the way electricity runs of pyroelectric materials through the rest of the circuit. This will trigger the motion detector to activate the alarm. If the entire field of view of temperature changes, this will not trigger the device. This makes so sudden flashes of light and natural changes in temperature do not activate the sensor circuit and cause false alarms.

IR Sensor Circuit Applications

Here is some of the IR sensor circuit that can be used as a reference application to be understood about the application of an infrared sensor on a variety of infrared detectors.

IR Sensor circuit

IR Proximity Detector Alarm Circuit

IR Sensor Circuit:

• IR Motion Detector
• IR Distance Detector
• IR Temperature Detector
• IR Beam Detector

These are examples of the basic detector circuit which in practice a lot to do with the application of IR sensor module and IR sensor circuit.

See also: Solar Tracker Circuit – Crystal Oscillator

A crystal oscillator datasheet is a technical specification related information from a crystal oscillator product. Things that are usually delivered on the datasheet is usually related to product features, operating conditions / electrical characteristics and package dimensions. This information is very useful in a design as well as information for the replacement product.

Crystal oscillator circuits are often designed around relatively few standard frequencies like 3.579545 MHz, 4.433619 MHz, 10 MHz, 14.318182 MHz 17.734475 MHz, 20 MHz, 33.33 MHz, and 40 MHz. Nominal frequency oscillator crystals we often see on television, computers, etc., in which frequencies are used in the application of a frequency divider, frequency multiplier, and the Phase Locked Loop (PLL). A crystal oscillator datasheet would be very helpful in terms of design, repair and even replacement of the product.

In addition to the above oscillator frequencies, of course there are many more nominal frequencies, like 32 768 KHz, 40 KHz, 4MHz, 8 MHz, 12 10 MHz, 16 MHz, 20 MHz and higher frequencies. Crystals can be produced for the oscillation in a wide frequency range, from several kilohertz to several hundred megahertz. Many applications call for simple crystal oscillator frequency associated with some other desired frequency, so that hundreds of crystal frequency standard made in large quantities, for applications ranging from toys to high technology in various forms of packaging. What about the crystal oscillator datasheet for those who need it?

How to find the crystal oscillator datasheet?

The crystal oscillator online sellers usually provide information in the form of crystal oscillator datasheet. If you have a product serial number of the crystal oscillator, so, then you can find a datasheet of the product online, commonly available in the pdf file format. Alternatively, it could make a request to my friends in the electronic forums. If answered, you will usually be given a link to the destination.

Click image for 4 Pin 4 MHz Crystal Oscillator Datasheet

Download 4 MHz Crystal Oscillator Datasheet

Direct way to obtain the crystal oscillator datasheet via Google is by directly typing a word or phrase by giving quotes, “4 pin 4 MHz crystal oscillator datasheet“. Just select and open the link and then save the file if it matches what you are looking for. Hope this helps you to get the crystal oscillator datasheet.

See also: Solar Tracker Circuit – DC DC Converter Circuit

Quartz crystal oscillator is a stable frequency generator using a Quartz Crystal as a resonator. In the crystal oscillator circuit, frequency stability is one of the most important references, which is a factor in the ability of various load conditions to provide a constant output frequency.

Quartz crystal oscillator used in Quartz Crystal is very small and thin section, or a quartz wafer is cut with two parallel surfaces metallised to create the necessary electrical connections. End of the oscillation frequency is strongly influenced by the physical size and thickness of a piece of quartz crystal. So it is a very important parameter to be strictly controlled and known as the “characteristic frequency” of the crystal. Alternatively, in other words, the size and shape determine the frequency or crystal cannot be used on any other frequency.

Quartz Crystal Oscillator

The uses of quartz crystal oscillators are intended to reduce or even eliminate the lowest levels of the factors that can affect the frequency stability. The factors that most often appear to affect the output frequency stability, among others, variations in load, temperature, and the change in DC power supply. Selections of the proper components are used in a resonant feedback circuit may also increase the level of frequency stability included the amplifier output. Of course still has the limitations of the RC and LC tank circuits normally.

So a quartz crystal is the frequency determining device with a very high degree of stability that is generally used in some type of oscillator circuit known as a quartz crystal oscillator (XO).

Quartz Crystal Oscillator in Use

Colpitts Quartz Crystal Oscillator

Quartz crystal oscillator circuit below should work on the frequency range 1.5 MHz to 8 MHz. A 30 pF of trimmer capacitor is used to adjust the frequency slightly toward the center frequency. 2N3904 transistor functioning as a buffer amplifier to function as a stabilizer frequency and increase the power output. This crystal oscillator circuit can be easily modified to change the frequency of RC components (R1, C1, and C2). Any changes can be monitored by a frequency counter.

1.5 MHz-8 MHz Colpitts Quartz Crystal Oscillator Circuit

Pierce Quartz Crystal Oscillator

The most simple crystal oscillator circuit is the Pierce oscillator. An FET is used as a amplifying device, as it has a high input resistance, the use of a fence 10M resistance. The crystal has a frequency of 2000 MHz, but a reasonable crystal can be used. 3.3 mH the RF choke provides a high impedance to alternating current load, while the passage of the drain current without the DC voltage drop (the choke had a resistance of 41Ω). The choke must be specially designed to maintain the desired inductance, while wearing DC, so make sure you use the choke is designed for the purpose. The impedance of the coil is then 41k of 2 MHz, which is sufficient amplification.

2 MHz Pierce Quartz Crystal Oscillator Circuit

Thus, the examples of Quartz Crystal Oscillator Circuit in this usage may shed some light to understand the quartz crystal oscillator.

See also: Water Level Sensor Circuit – Crystal Oscillator

Crystal oscillator circuit is a simple oscillator circuit when we look at the schematic diagram. A crystal oscillator circuit is nothing but a replacement of an ordinary oscillator network, which is a combination of LC. This simplicity is also reflected in the number of physical components that are very compact, which occupy your printed circuit board. You live alone design the layout of components in such a way as to give the best results.

Based on experience in designing a crystal oscillator, I can say very easily. If it is limited to a curiosity about how a crystal oscillator circuit is working, then the frequency counter is readable display a very stable frequency. Without having to make a PCB, simply by connecting the pin connections between the components involved.

Colpitts Crystal Oscillator Circuit

However, for optimal results should be required data regarding the technical specifications of the crystal oscillator, and the components involved. You can just download the datasheet the crystal oscillator, and if necessary for the transistor or integrated circuit (IC) as well. In addition, the layout of the components that also affect the quality of the output frequency. Here below are some of the crystal oscillator circuits for practical use.

32.768 KHZ Crystal Oscillator

32.768 KHz Crystal Oscillator Circuit

The following oscillator circuit using a crystal to produce 32.768 KHz square wave output, and then fed to a 15 stage binary counter with 1 second square wave output. In the oscillator circuit diagram of the IC using a CMOS inverter 4069, to produce a better waveform, but a single transistor can be used. As a note, if you do not want to buy a 32.768 KHz crystal, can usually be found on a watch or computer mainboard that is damaged or not used anymore.

EM7604, Low Power Crystal Oscillator 32.768 KHz module can also be an option. EM7604 is an advanced low power CMOS circuit intended to be used together with a 32 768 kHz tuning fork crystal as a low-frequency clock oscillator. Except the crystal, no other external components are required. The device combines excellent oscillator stability with very low power consumption. It is guaranteed over a very wide supply voltage and temperature range. In order to Achieve a high-frequency accuracy, the matched crystals should have a ± 20ppm tolerance or tighter.

EM7604 - Low Power Crystal Oscillator 32.768 KHz

1 MHZ Crystal Oscillator

Crystal oscillator circuit with the output frequency of 1 MHz as a base frequency of a signal generator using TTL SN7490 decade counter IC. Basis of this frequency will be divided into several lower frequencies through a frequency divider 10 and 2.

1 MHz Crystal Oscillator Circuit

10 MHZ Crystal Oscillator Circuit

10 MHz Crystal Oscillator Circuit

See also: Water Level Sensor Circuit – DC DC Converter Circuit

If you want an oscillator frequency with high accuracy and very precise frequency, then the answer is a crystal oscillator. Electronic oscillator circuit is built through the mechanical resonance of the vibrating crystal of piezoelectric material. Piezoelectric resonator of the most commonly used is the quartz crystal material. So the type of oscillator is known as “crystal oscillator.”

The use of frequencies, usually crystal oscillators used as reference frequencies. The use of a crystal oscillator in electronics such as a stable clock signal from a digital integrated circuit, a steady and stable frequency signal at the transmitter and receiver, and even very often found in quartz watches as a time tracker. Quartz crystals are also found inside test and measurement equipment, such as counters, signal generators, and oscilloscopes.

Crystal Oscillator and Quartz Crystal

Crystal Oscillator – Buy or Build

As stated already understood, that a crystal oscillator can be used as a reference frequency in a variety of electronic applications. Since it has a characteristic frequency of accurate and very stable. For the purposes of the use of practical, especially for the electronics world has two choices to buy a crystal oscillator package, or build it yourself using a quartz crystal in accordance with the desired frequency.

A crystal oscillator package is widely available commercially within a fairly wide frequency. It is packaged in a tin box and have some pins are available, and is accompanied by a crystal oscillator datasheet concerning the technical specifications and instructions. By purchasing this oscillator package seems very practical and ready to be used in accordance with the selected frequency.

This crystal oscillator product will be durable in use when it followed the requirements of its use, especially regarding the working voltage, and further guarantees and security, both physically and harmonic frequency output level is low, because it usually has an internal RF filter and packaged in a tin box that serves as a shield.

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When you want to build a good crystal oscillator is also not difficult just by a simple circuit using integrated circuit or transistor can have a resultant very stable frequency. For example, if you use the IC, then you need to datasheet of the IC and quartz crystals. Even in the datasheet has been accompanied by examples of the use of additional component’s table capacitors and resistors. IC is used to generate a low frequency while the transistor can be used up to frequencies of hundreds MHz.

10 MHz Crystal Oscillator Test Circuit

So the above explanation is to consider the job specification quartz crystal itself, and the active components are used. Due to an integrated circuit (IC) or a transistor having its own operating frequency range. For example, the application of Phase Locked Loop (PLL) ICs, and transistors can be used both, because the frequency range between hundreds of KHZ up to MHz.

Crystal Oscillator Tutorial

Some sites that can be used as a reference to learn about how to build a good oscillator, you can follow the link here and here. Happy studying and good luck in working with a crystal oscillator.

See also: Water Level Sensor Circuit -  Solar Tracker Circuit

DC DC converter circuit is an important part for portable electronic devices that use batteries as main power supply, such as laptop computers, mobile phones, and other such devices. As in the usual laptop needs a DC voltage range 19V-20V to operate and to use battery operation has been mounted internally or use external power supply with AC power as a source.

What to do when the only available as a source of DC power that is even much lower than 19V? Here, it takes a DC DC converter circuit by using a lower voltage to produce the required output voltage of 19V. Most DC to DC converter also regulated the output.

Another reason, the voltage drop due to the use of dry batteries. So that a sub-circuit is required to maintain a fixed output voltage equal to input voltage change to the lowest possible voltage levels. Switched DC DC converter circuit to offer this feature, including the use of laptops in the vehicle where the available input voltage 12V battery.

Car DC DC Converter Circuit Diagram

The following DC DC converter can function as a laptop power supply and can be used to charge your laptop battery. It can be connected to the cigar lighter socket of the car to produce a supply of clean and stable DC 19V/5A, from a 12V battery supply. Enough and more for a laptop!

Car DC DC Converter Circuit

Car DC DC Converter - PCB - Parts List

This DC DC Converter uses a SMPS controller IC UC3843 in the design, which is a fixed frequency current-mode PWM controller. It is specially designed for Off-Line and DC to DC converter applications with minimum external components. For the voltage amplifier transistor, used as a driver BD139/BD140 pair to amplify the final IRL2505 MOSFET transistor. Visit the following site to build a DC DC converter circuit.

See also: Touch Switch Circuit – Solar Tracker Circuit.

If you want to build your own solar-energy needs, you need a solar tracker. Use of solar tracker is directing a variety of payloads into the sun, in the form of reflectors, lenses, photovoltaic, or other optical devices. In order to regulate the movement of the pointing needed a solar tracker circuit.

By using a solar tracker circuit can be determined where the installed solar panels that track the movement of the sun in the sky. So that it ensures that the maximum amount of sunlight strikes the panels throughout the day.

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How to Solar Trackers Work

There are several types of solar tracker, which are grouped into a single axis and dual axis models.

• Single axis solar trackers can have horizontal or vertical axis. Horizontal types used in the tropics where the sun will be very high in the daytime, but the days are short. Vertical type used in high latitudes where the sun does not get very high, but the days of summer can be very long.
• Dual axis solar trackers have horizontal and vertical and the axle so it can track the apparent motion of the sun just anywhere in the world. This type of system used to control the astronomical telescope, and so there is plenty of software available to predict and track automatically the movement of the sun in the sky.

When compared with the price of PV solar panels themselves, relatively low cost solar tracker. However, to have a good quality solar tracker of course prices are released quite expensive. So a DIY solar tracker circuit may be a choice you need.

To give an idea in general, what you should know about a solar tracker, following some solar tracker circuit equipped with a printed circuit board (PCB) from several internet sources.

Solar Tracker Circuit Diagrams

LDR Solar Tracker Circuit Diagram

Solar tracker monitors the position of the sun using two Light Dependant Resistors (LDRs) and made ​​the decision to move the solar panels to properly oriented to the sun. H bridge is the output of the configuration which will drive the gear box up to 500mA at 6-15V input voltage, both forward and backward. It will not only track the sun, in the dark, it will of track a bright light. source

LDR Solar Tracker Circuit - LM1458

LED Solar Tracker Circuit Diagram

Includes all the components and materials required to build a sensor and circuit for single axis tracking (dual axis tracking requires two kits). The solar tracker circuit can drive up to a 1A DC motor or can be used to switch a relay. source

LED Solar Tracker Circuit - LM339

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Another resource for Solar/Sun Tracker DIY. Hope this can help your DIY solar tracker plan and successfully build on the reference solar tracker circuit.

See also: Touch Switch Circuit – Water Level Sensor Circuit

Water level sensor circuit is a circuit which is useful for detecting the presence of water in a tank. This circuit will work if the sensor probe is connected by water, and the signal will, then be transformed in an advanced circuit with a specific purpose in the form of sound, LED display, and or drive a relay to disconnect or connect the power source.

A water level sensor circuit is more complex can be designed based on the desired features. When the desired height it is necessary to detect some multiple probe sensors, each of which signals from the sensors can be further functionalized. For example, various heights in the tank will be detected by the height of the water and then be displayed in the form of LED displays.

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PIC12F683 Based Water Level Sensor Circuit

Water level sensor is a fairly easy project using PIC12F683 as a processor. Probe sensors using solid copper wires. The output of the detection results in a BEEP sound. If you would like to build a water level detector can visit the source.

PIC-Based Water Level Sensor Circuit Diagram

Water Level Sensor Circuit with Relay-Switch

Water Level Sensor Circuit with LED Indicator

This circuit aims to monitor the height of the water tank in the attic from the basement as a control room, for example, kitchen or warehouse. The features of this sensor can be viewed at the source.

Water Level Sensor with LED Indicator

Wireless Water Level Sensor

Advanced features of a water level sensor circuit, where the sensor probes that are far away from where we monitor the water level. These sensors are usually placed in-water reservoirs. Of course for this purpose required a transmitter-receiver module package, this device is called a water level sensor wireless.

Wireless Water Sensor with Siren

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Water level detector will allow you to monitor the water level in the tank located on the top floor or above the tower, or the storage of water in lakes or rivers. Build one for you from some of the water level sensor circuit.

See also: Touch Switch Circuit

Touch switch circuit is a circuit used to control electronic devices simply by touching a sensor. Here below are two touch switch circuits that can be used to control your electronic equipment such as a touch light switch. Both are simple touch switch project that comes in the kit are available in the market. So, you do not have to bother anymore to create a touch switch PCB.

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Touch Switch Circuit Diagram – CD4011

This circuit is very simple and easily constructed using an IC CD4011, where two plates of the sensor are connected as a flip-flop on pins 9 and 13 of the IC 4011. This touch switch circuit uses only eight components.

Touch Switch Circuit Board

Pin 9 and 13 of the IC is «SET» and «RESET» contacts from the flip-flop. This IC CMOS type requires a very low current on the gate to control it. This high-sensitivity circuit made possible a touch operation. Both gates are held at logic state «1» continuously by using two resistors R1 and R3 that connect them to the positive supply rail. This resistor has a resistance that is greater than 10 Mohm. If now we touched a set of contact resistance of skin to close the circuit between the gate and the corresponding negative supply rail.

Touch Switch Circuit - CD4011

This kin resistance for small areas of ​​skin is usually much lower than 10 Mohm and effectively brought to the gate logic state «0» which makes changing the condition of the flip-flop. For any given state of the FLIP-flop is set in accordance touching contacts would make a circuit to reverse the country’s balance and force the switch to switch. It used as a relay switch is driven by a transistor which is driven from the out put of the flip-flop.source

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On-Off Touch Switch Circuit Diagram – NE555

With this switch circuit, you can turn on almost all electrical devices and switches automatically turn off within a short time later. Since you’ll notice you can determine how much subsequently – less than a second to more than one minute – just by changing the value of one resistor. source

Touch Switch Circuit - NE555