A Brief Guide to Electrical Relays for Dummies

Simply put, a relay is a kind of switch that is operated electrically. Many relays make use of an electromagnet to make a switch to function. However, they use other operating principles too. To understand different aspects of relays, follow this brief guide for electrical relays for dummies. It focuses on the definition of relays, their types, and applications.

Electrical Relays for Dummies

What are Electric Relays?

The functions of relays are to control a circuit or multiple circuits by a separate low-power signal or one signal, respectively. The first use of relays was in telegraph circuits. Currently, they are widely used in telephone exchanges.

Some Common Types of Relays

Relays are available in various types and forms for performing different functions. Some common types are discussed below:

Contactor Relays

An electric motor or other electrical loads require high power for their operator. Contactor relays can handle that high power. They switch devices in control and auxiliary circuits.

Solid-State Relays

Such relays control power circuits with the help of a semiconductor device. They apparently use no moving part for switching.

Protective Relays

Protective relays perform the function of protecting electrical circuits and transmission lines from short-circuits, overloads, and other faults. They come with attuned operating features and sometimes with several operating coils.

Protective relays are still in use, but digital instruments are mostly used these days for performing such functions.

Magnetic Latching Relays

The relays move their contacts in one direction with one pulse of coil power and then move the contacts back with redirected pulse. They are effective in applications where interrupted power has no influence on the contacts.

Railway Signaling Relays

The relays are larger considering the amount of currents and voltages they handle. Their contacts are spaced widely for protecting the system from short-circuits and flashovers.

Electrical Relays for Dummies: Applications

Relays are used in systems where it is required to regulate a high power circuit with a low power one.

Relays were first used in telegraph lines where they did the job of regenerating weak signals for further transmission. Similarly, early computers used them for logic and working registers.

Relays are used for intricate switching systems such as telephone exchanges. They are also used in production lines and machines tools for controlling the automated systems. They control a high current with small wiring and contacts in an automobile.

Another condition where relays are extensively used is in the radioactive waste handling machinery’s control panels. They are suitable for such conditions because of their better resistance to nuclear radiation than semiconductors.

Where to Buy Relays

Many manufacturers produce and market a broad range of relays and supporting accessories. All electrical supply stores, either brick-and-mortar or online, are supposed to have an excellent collection of relays for sale.