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 triac circuit was taken from an article in the July 1970 Radio Electronics magazine. Note the...
Signals ranging from a few millivolts to a few volts can be used to excite a relay with this...
This circuit was found in American documentation from the 90's. The transformer determines the...