Found in American documentation from the 1980s, this circuit prolongs the ringing of a doorbell or chime powered by a 6 V continuous voltage. The transistor can be a BD136.
This circuit from the 70's used germanium transistors and operated in the range of medium and...
The figure shows how to convert a rectangular signal into a triangular signal using an integrator. The...
This circuit was found in a National Semiconductor manual from the 1970s, appearing in articles and on...