This circuit was found in a 1968 US publication. Transistors used are uncommon today. The circuit can be adapted to operate with modern equivalent components.
This circuit for VCR recording heads was found in the February 1990 issue of Radio Electronics magazine....
This very simple continuity tester uses a small 1.5 V lamp (type used in flashlights). Can be...
This commercial radio with 3 earphone listening transistors was manufactured in Japan in the...