This circuit with its light source was found in American documentation two years 70. Or transformer of the type found in small transistor radios of the time. The transistors are general-purpose.
This circuit, found in an old magazine of the year 1968, uses a Power germanium transistor. This...
This sequential circuit with an optical coupler was found in a Popular Electronics from the 90s to...
This guitar effect circuit was found in a 2002 documentation. The circuit can be powered by a 9 V...