This 4-voltage power supply using zener diodes has a maximum recommended current of 25 mA. The circuit was found in the May 1966 Radio Electronics magazine.
In the figure we have a simple signal tracer circuit to be coupled to the volume control of an AM...
This circuit was found in documentation from the 90s, using components from that time. The...
This circuit, obtained from old documentation, allows the recovery of sulfated batteries. The...