A few weeks ago, I wrote about fixing the VDO windshield washer pump in a vintage European car. As part of that, I quickly ...

Have you ever needed to power a 12-volt relay in a circuit but only had 6 or 9 volts available? This simple circuit will solve that problem. It allows 12-volt relays to be operated from 6 or 9 volts, ...

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 ...