Found in an Elektor from the 90s, this circuit can be powered directly by the power grid. The circuit uses a rectifying bridge that can be replaced by 4 common diodes.
We found this circuit in the June 1991 issue of Radio Electronics magazine. The integrated circuit is...
This polarity test or indicator indicates the polarity of a power line by LEDs. The circuit is...
This circuit is from Motorola's 1990 Linear Databook. The transistors allow equivalents and the...