Progressive relay switch (CB23775E)

This progressive circuit has a lock allowing coded activation. We found this configuration in Radio Electronics magazine from October 1961.

Power supply 0 to 20 V (CB22176E)
The output current of this power supply depends on the power transistor and the transformer and...
9 to 330V Converter (CB25840E)
This voltage inverter uses a small transformer. The circuit was found in the April 1995 issue of...
Preamplifier (CB21749E)
This 1969 Popular Electronics circuit was based on the then recently released BC109, today with...