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Musical & effects
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Metal Detector Circuits
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Air-Gas Detection Circuits
Human Sensing Circuits
RF & Radiation
Optical Sensing Circuits
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AC to DC & DC to DC
Solar Cell Circuits
Micro Power Circuits
Switching Power Supplies
Light Laser LED
Digital to Analog
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Data Bus Circuits
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Current to Voltage
Frequency to Voltage
RF Converter Circuits
Sine to Square Wave
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voltage to frequency
Period to Voltage
Video Wall circuits
TV Video Circuits
Motor Control Circuits
8051 / 8052
PCB CAD Software
Car bike Circuits
555 Timer Circuits
Remote Control Toy
H Bridge Circuit
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
Meter Counter Circuits
Multiple Continuity Tester
The continuity tester is a handy adjunct to an ohmmeter. The unit or component whose continuity is to be checked is connected between terminals E1 and E2..
Self-Powered Fast Battery Tester Schematic
This circuit runs a fast battery test without the need of power supply or expensive moving-coil voltmeters. It features two ranges: when SW1 is set as shown in the circuit diagram, the device can test 3V to 15V batteries. When SW1 is switched to the other position, only 1. 5V cells can be tested. FET Q1 provides a constant current generator biasing
Servo Tester Using A 4538
Everybody who regularly works with servos will know several instances when such a servo tester will come in handy. The function of a servo tester is to generate a pulsing signal where the width of the positive pulse can be varied between 1 and 2 ms. This pulse-width determines the position the servo should move to. The signal has to repeat...
Simple Cat.5 Network Tester
This circuit came from a need for a quick and dirty network tester that could be operated by one person. All the commercial units I tried required a per..
Simple Cat.5 Network Tester
This circuit came from a need for a quick and dirty network tester that could be operated by one person. All the commercial units I tried required a person at the other end to check the remote LEDs, as the transmitters could not be made to cycle through the test continuously to allow one person to check both ends. It must be noted that this uni
Simple Remote Control Tester
In the circuit here it simply biases the BC558 which, in turn, makes LED D1 flash in sympathy with the telegram from the remote control. The preset in the circuit determines the sensitivity.
The circuit in the diagram is a very handy tool for rapidly checking all kinds of thyristor (SCR, triac, ). In case of a triac, all four quadrants are te..
Crystal tester circuits using BC107
You cannot use a multimeter to check a crystal. You should have a this circuit, because it can check a crystal 100Khz to 900Mhz, easily to make and cheap.The..
Flyback transformer tester circuit using 2SC828
The circuit tests a flyback transformer of the televisions that the result is a simple, easy and cheap to build. One of my friends is TV repairman colors -..
Non contact ac detector voltage tester using CD4060
Tools that features equivalent of a professional, easy to use, cheaper, and more importantly, safe for use. For checking to find AC 220 Volt or 120V or call..
Simple transistor tester circuits
This is the Transistor tester into the Circuit or PCB. When your project do not works, the tester electronic parts or..
just sanity check transformers
Designing a true constant-current AA NiMH charger, and want to select a power supply that will be just right. I want a high enough voltage to that the CC transistor doesn`t saturate, yet low enough voltage to reduce the power dissipation in the transistor. I plan to build a unit that will charge two seperate banks of 2 NiMH cells in series at0....
A simple remote control tester circuit diagram
Here is a handy gadget for test- ing of infrared (IR) based re- mote control transmitters used for TVs and VCRs etc. The IR signals from a remote control transmitter are sensed by the IR sensor module in the tester and its output at pin 2 goes low. This in turn switches on transistor T1 and causes LED1 to blink. At the same time, the buzzer beeps
Servo-Checker JR / Futaba
The first timer IC555 creates a negative trigger signal of approximately 45Hz (a trigger impulse every 22ms, DO NOT exceed 50Hz for proper servo function). The second timer IC555 modulates a positive square signal from 0. 9ms to 2. 1ms every 22ms, a method commonly known as pulse width modulation (PWM). The modulated pulse width provides the...
12V Vehicle Electrical Wiring Tester Circuit
12V Vehicle Electrical Wiring Tester Circuit This little tester is useful for checking vehicle electrical circuits. Two LEDs indicate whether..
In-Circuit Transistor Tester
In Circuit Transistor Tester Schematic Here is a circuit that can indicate the condition of a transistor by using two LEDs. A good NPN transistor..
Infrared Remote Control Tester Circuit
Infrared Remote Control Tester Circuit This is a simple circuit you can build in order to test infrared remote controls. The circuit uses an..
SCR TESTER CIRCUIT The Device under test cathode, anode and gate are connected to the unit`s CATHODE, ANODE and GATE terminals,..
Although you don`t find SCR and Triac in all electronic equipment, this does not mean that both are not important components. You need to learn how to test it so that when you come across one in the future you will know if it is good or bad during troubleshooting. You can test these components using meters but with the SCR/Triac tester you will fi
FETs can be found in the power section, LCD inverter, UPS, Amplifier, Monitor B+ and S-correction circuit, ATX power supplies and etc. When this component fails, one has to use a meter to test it to check if it is good, shorted, openor leaky. The meters can be a normal multimeter, specialize FET tester like the Peak Atlas Tester, Sencore Cricket...
Logic Probe Tester Circuit
Logic testers are simple but very helpful devices in testing digital circuits. A logic probe can be designed in many different ways. In this particular des..
Infrared Remote Control Tester
This small InfraRed Remote Control Tester circuit is used for checking the operation of an infrared remote control unit. The circuit is based on the idea of connecting a piezo buzzer directly to an IR receiver IC. The TSOP1738 integrated IR receiver accepts, amplifies and demodulates the IR signal from the remote control, producing an output with
Network RJ45 Cable Tester Circuit
This is a multifunction RJ45 network cable tester. It is the design of the network cable (RJ45) test, and telephone (RJ11). It is cheap and easy to use. It works for network, telephone, cable with RJ45 half Registered Jack plug immediately indicate whether a crossover network cable or straight, flashing a yellow or green LED. If something is br
Soil Moisture Tester Circuit
For those of us who don t like to get their hands dirty, this simple soil moisture tester quickly checks the state of their plants and how much attention t..
Simple LED Tester
Do not let its extreme simplicity deceive you â€” this thing is useful! I have made many over the years and have even given some away as gifts. Yes multimete..
555 RC Servo Tester Circuit
Servo refers to an error sensing feedback control which is used to correct the performance of a system. Servo motor is a DC motor equipped with a servo mec..
Crystal Tester Circuit
The idea for this crystal tester circuit sprung out of the need of testing a large number of oscillator crystals lying unused in a big hobby box. testing the crystals one by one without the appropriate device would have been very slow and a time consuming task. Commercial crystal testers are however very expensive, that is why this simple electron
T1 and XTal have formed an oscillator. C1 and C2 are voltage divider for oscillator. if the XTal is safe, the oscillator will work well and its output voltage will be rectified by C3, C4, D1 and D2, then T2 will run and LED will light. The circuit is suitable to test 100KHz - 30MHz Xtal.
Simple but reliable car battery tester
This circuit uses the popular and easy to find LM3914 IC. This IC is very simple to drive, needs no voltage regulators (it has a built in voltage regulator) and can be powered from almost every source. When the test button is pressed, the Car battery voltage is feed into a high impedance voltage divider. His purpose is to divide 12V to 1, 25V (or l
Mosfet TESTER Circuit
Frequency Meter Circuits
VU Meter Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial