This circuit for audio applications was found in an English magazine from the 80's. The circuit has a pass band below 3 kHz making it ideal for telecom applications.
This circuit was found in a 1967 Electronics World. SCRs are according the controller load,...
We found this configuration in an early 1977 publication. The PNP transistor may be the BC558 and...
This circuit of a Popular Electronics is intended to control a wiper. The circuit consists of a...