Found in American documentation from the 1980s, this circuit prolongs the ringing of a doorbell or chime powered by a 6 V continuous voltage. The transistor can be a BD136.
This 32 A circuit uses SCRs of the time. We found it in a 90s General Electric documentation. The...
This amplifier stage with 1 power transistor was found in the Radio Electronics magazine of...
This transceiver is also low power, but this time, it can generate signals in the 144 MHz band. In the...