This circuit was found in American documentation from 1966, but it can be assembled with a modern equivalent transistor. The circuit is based on a mechanical tuning fork with a coil feedback system.
This different astable configuration was found in one in a 1974 Ferranti transistor manual....
We found this circuit in an American 80's documentation. The resistors must be of high precision...
This switch or band selector for receivers was found in a Popular Electronics from the 1990s. The...