The circuit presented is a Japanese commercial radio for AM with 50 mW of output power, powered by 9 V. The circuit is from the 60s, having been found in documentation of the time.
Charcoal microphones are rare today. In the figure we have a circuit that shows the use of one of...
This circuit was found in an old American magazine for radio amateurs. The circuit is based on a...
We found this circuit in Ferranti's 1974 transistor manual. Transistors are general-purpose types...