This simple circuit makes use of neon lamps to indicate the voltage of a power grid. The lamps are common neon and the circuit indicates whether the voltage is 110 V or 220 V.
The CK722 transistor used in this circuit is one of the first commercial types in the world. The...
This automatic dimmer for incandescent lamps was found in a European publication from the 1980s. The...
This traditional doubler configuration with the 555 can be found in other articles on the author’s site....