This circuit visually indicates that a high voltage is present in an outlet or other point. The neon lamp is common, and the appearance of the assembly is suggested in the same figure.
This interesting circuit measures the distortion of the sinusoidal voltage of the power grid. We...
The operational amplifier used in this old application is not common today, but more modern...
Used in 1950s CW receivers, this type of circuit used germanium transistors. The circuit has...