Found in documentation from the 1980s, this circuit is used for resistive loads (incandescent lamps). The triac must be equipped with a heat sink.
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...