Relays, Timers & Counters

Relays are electrically operated switches. Relays include at least one energizing circuit and at least one contact, or controlled, circuit.  The energizing circuit, which is typically a single-phase low-power signal of no more than 20 amps, controls one or more contact circuits, which can be high-voltage. When a current passes through the energizing circuit, it opens or closes the contact circuit – stopping the current or allowing it to pass through.  The functionality and application of relay switches are defined in large part by the number and combination of poles and throws they have, and if the throws are normally open (NO) or normally closed (NC).