This old 1 W audio amplifier transistor circuit is from a 1967 Japanese magazine. The transistors are germanium of the time and the type transformers found in similar equipment of the time.
The circuit in the figure uses the four current amplifiers of the LM3900 to generate a sawtooth signal...
This circuit was found in an old Motorola documentation from the 70s, as it uses one of its...
This circuit for an optical audio link using LED or LASER was found in a 90s QST magazine. The circuit...