This simple circuit is a continuity test that, in addition to testing resistors, can also test other components. Power is provided by batteries and the LED can be of any color.
This simple transmitter for the AM range was found in a Popular Electronics magazine from March...
This circuit was found in a 1968s American. Transistors are of general purpose and the input is a...
This circuit with SCR was found in an old documentation. The SCR can be the TIC106, and the...