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 ...

The fan center’s purpose is to control when the indoor fan turns on. Before the integrated gas control board, the indoor fan on gas and oil furnaces would either turn on at the same times as the heat ...

Relays and contactors use a variety of technologies to switch signals and power connections. Many devices called relays use similar techniques and topologies, but the terminology can be confusing.

My July 3 column covered the theory and operation of potential relays. This article covers potential relay ratings and specifications along with systematic troubleshooting. Here is an example of a ...