Free Circuit Diagram

Metronome is very important tool if you studying music playing. There are mechanical metronome device in the past, but today, electronic metronome is much more popular since it can be very simple, compact/small, reliable, and also has the most interesting feature: cheap. Here is one example of the electronic metronome schematic: Parts: [...]

This audio power amplifier circuit is simple and robust, and use discrete component available on many electronic part stores. The final transistors use 2N3055 and MJE2055. Here is the circuit’s schematic diagram: The MJE2055 is an npn transistor, but the configuration with TIP42A make the whole combination of TIP42A and MJE2055 are seen [...]

Using only transistors as the active components, we can build a simple and low cost TTL-to-RS232 level converter. It uses only two transistors as the active components. Here is the schematic diagram of the converter: /caption] You can use any small signal transistor for this RS232 converter circuit. You can see [...]

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) [...]

It would be cool and elegant to a have mechanical sound character for our electronic metronome. This electronic metronome circuit will produce such sound, making your life more fun. Here is schematic diagram of the circuit: The metronome circuit consists of two 555 oscillators. The first oscillator is used to make high frequency [...]

This tone control circuit use very popular Baxandall configuration, a simple circuit configuration that provides boost and cut control in continuous manner. This circuit is very cheap to build, and it’s commonly implemented in commercial product. Here is the circuit’s schematic diagram: The transistors can be substituted by any general audio transistors with [...]