This circuit uses a contactor having been found in a 1987 publication. More modern equivalent devices may be used. The circuit has neon indicator lamps.
This didactic circuit makes the sequential activation from 0 to 10 to demonstrate the functioning of a...
This power source was found in an old Argentine publication from 1973. The transistor could be the...
This circuit operates at a voltage of 1.3 V from a single mercury cell. We found in an old...