This is the basic configuration of an operational amplifier sample & hold circuit. The FET and transistor are commonly used. The circuit is from an 80's documentation.
This circuit was found in old American documentation. Transistor is general purpose and coil rated...
This tiny photocell-powered audio oscillator was found in a book on transistors from the 1960s. The...
This circuit was found in a Hands On Electronics from the 90s. It is intended to supply old tape...