This is the factory setting (National Semiconductor) of the TDA2006 as an audio amplifier. The circuit works with 24 V and the diodes can be 1N4148.
In a modern version this circuit can use an LED in series with a resistor in place of the lamp. The...
This bistable circuit with SCR for direct current was found in the Radio Electronics magazine of...
The configuration shown in the figure uses two NPN transistors activating the load when the input...