This simple circuit was found in a Japanese magazine in 1967. The circuit is listening on a headset and the coil is 50 + 50 turns of wire 28 or thinner on a ferrite rod.
This solid-state relay (SSR) or shield was found in a 1995 Electronics Now. The transistor can be...
The output current of this circuit reaches 12 mA. The zener diode determines the output voltage. The...
In the figure we have an IF amplifier step using a MOSFET. The circuit was found in a 1980s...