This circuit was found in a 1967 Electronics World. Transistor Q1 can be a TIP321 and Q2 can be a BC558. The indicator lamp is optional.
September 2016 - It can be obtained from Mouser Electronics new LED indicators for panel mounting...
This circuit provides 2.5 W of power with 6 V supply and 4-ohm speaker. We found it in the Radio...
We found this circuit in 1980s documentation. It can be used independently as CW or by exciting a...