Free Circuit Diagram

Our reader Andrea (andrea[dot]perugia[-at-]gmail[dot] com) sent his circuit to us, and he creates the circuit for educational intent. The main purpose is to show that you can toggle an output state electronically, although physically you use only a push button switch. Here is what he said about the cicuit : This simple [...]

This circuit is not a voice operated switch (VOX) because this circuit is too dumb to differentiate between musical sound or human voice. This is rather a sound activated than voice activated. One interesting application is to control your disco lighting automatically by the musical sound from high power amplifier, when the music signal is [...]

Feedback in public address amplifier is something that should be avoided. The ideal solution is by adjusting the microphone and the speaker position, but it’s not always possible in many situation. Using frequency shifter to change the output frequency 10Hz lower than the input frequency can solve the problem, but it’s too expensive for [...]

This circuit is similar with our previous dimmer circuit, but the gate control is full-wave rectified using diode bridge. This circuit can be used to replace electric switch for your incandescent lamp, brushed motor, soldering iron or heater. Here is the schematic diagram of the dimmer switch: Please note that his dimmer switch [...]

A DC-to-DC step-up converter is traditionally implemented using transformer, working by converting the DC voltage to AC Voltage, step-up it using transformer, then rectify and filter the transformer’s output to  get a higher DC voltage. Using a switching method, we can step-up a voltage without a transformer. We just need an inductor which is driven [...]

If you need a negative supply for op-amp or just need negative bias voltage while operating from a single supply voltage (for battery operation for example), this circuit helps providing the negative supply for you. The circuit is based on charge pump driven by 555 switching circuit. Here is the schematic diagram: [...]