This circuit was found in a 1971s English magazine. We can still assemble it using BC548 transistor. The other components are common. The supply voltage of 6 or 12 V depends only on the relay.
This circuit was found in an American 1980s documentation. The components are current but most...
This circuit was found in an old GE SCR manual. The SCR must be in accordance with the relay and...
This circuit measures millivolt voltages. The corresponding current range of the multimeter can be...