Found in older Signetics documentation, this circuit generates signals from 30 Hz to 25 kHz. Operational amplifiers are from the time, as is the matching pair of transistors.
The 556 consists of a double integrated circuit 555, which can be replaced by them in this...
We found this circuit in a Radio Electronics from January 1967. The SCR is already the C106, which...
This circuit is from American documentation from 1970. It can be designed with a BC558 and for the...