This very complex circuit in terms of the number of transistors was found in Radio Electronics from March 1966. The circuit is for low impedance headphones. The transistors are from the time.
We found this circuit in a 1978 documentation. The SCR conducts when the regulator's output...
The outputs of this timer or CMOS timer configuration with the 4011 integrated can be connected to load...
This circuit is from 1995 documentation. When the phone is lifted, the relay closes its contacts by...