Using 5 V relays, this circuit can be used as a control shield for microcontrollers. The circuit uses relays, and the motor voltage is independent of the control voltage.
This circuit using an operational amplifier was found in old American documentation. It can be...
If the circuit oscillates, emitting sound, it is because the transistor is good. This simple...
Like the previous circuit, this is used in the analog part of the telephone lines. The same...