This simple circuit for motors that depends on the MOSFET used was found in the January 1998 Electronics Now magazine. The motor voltage does not need to be the same as the oscillator.
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...