This simple circuit for a common 110 V power grid was found in a 1980s American documentation. The circuit uses neon lamps as indicators.
This configuration for latching automation using relays was found in Radio Electronics magazine from...
This circuit was found in Motorola documentation from the 1980s. PUTs are not common components...
This circuit is based on a regulator component that consists of a transistor and zener in the same...