The 1: 1 transformer on this circuit found in a 1967 Electronics World can be wrapped around a small ferrite rod. The circuit operates with 600 to 6 000 Hz control signals.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...