What is the NO SPST normally open relay? The NO Normally-Open SPST (Single Pole Single Throw) relay has an opened circuit state when no current is applied to its coil so basically it disconnects the ...

What is the normally closed SPST relay? The NC Normally-Closed SPST (Single Polse Single Throw) relay has an initial closed circuit state when no current is applied to its internal coil therefore it ...

A friend once asked about the block of relays pinned to a board behind my car's dash. To him relays were the mysterious little boxes that some cars inexplicably required to operate a horn. More than ...

Not long after I began contributing to Hagerty eight years ago, I wrote a detailed four-part piece on electrical relays and how they work in cars. You can still find the articles here (Part I: Why We ...