When working around mains voltages, it can be useful to know whether a given circuit is live or not. While this can be done by direct connection with a multimeter, non-contact methods are available ...

This file type includes high-resolution graphics and schematics when applicable. Low-power applications such as e-meters (electricity or energy meters) often require a simple ac line-powered supply ...

Providing power via contact-closure circuits historically required a new third wire, but perhaps no longer. Say the words “solid-state relay” (SSR) and most engineers also naturally think of two ...