Free Circuit Diagram

Finding electronic circuit schematic diagrams is fun if you’re doing an electronic building as a hobby. Learning already made circuit schematic diagram is a good start to design your own circuit. Sometimes we think that designing our own circuits is smart, showing to people that we capable to design our original circuits. [...]

A crystal tester circuit is very simple, it contains only oscillator and detector inside. This crystal tester circuit uses one transistor for the oscillator and one transistor for the detector. Here is the schematic diagram of the circuit: The mechanism of this crystal tester is very simple. If a good crystal is connected [...]

Testing whether a transistor is shorted or open usually done by ohm meter. You test if the base to emitter  or collector permit a current flow in one direction. Here is the circuit’s schematic diagram: The 555 timer ( IC1 ) operate as a 12hz  oscillator. The output of this oscillator (pin 3) [...]

This circuit included in the category astable multivibrator. This circuit is used to test  N-Mosfets (the power kind e.g irf830), whether it works or not. If it is not working, the LED will not flash. If Mosfet is working it will operate in the astable multivibrator circuit causing the Led to flash. Here  is the [...]

This transistor tester is very helpful if you need to sort bulk transistors. In  some market, if you know where to find it, sometimes you can get transistors sold in kg unit, not in single peaces unit. You can buy 1 kg of transistors with really cheap prices. Don’t be too happy right now because [...]

This video is a tutorial of lamp dimmer using PWM. This video shows the use of PWM for lamp dimmer. In this video, the PWM kit uses a 555 IC. The brightness of the lamp is dimmed by changing the pulse. If we up the pulse slowly, the intensity of the lamp getting brighter. Here [...]