This article is about Different Types Of Relays. A Relay is a switching device it works to change the state of an electric circuit or electric current from one state to another. Relays are classified according to their working and structure. Well, known categories include protective, regulating, reclosing, auxiliary, and monitoring relays. Protective relays monitor these parameters: current, voltage, and power; and if these parameters violate from mentioned limits they generate an alarm to inform the situation of the circuit. Pin configuration of Relay.

Different Types of Relays

Different Types of Relays

There are many types of relays, depending on the operating principle relays are classified into different types such as:

  • electromagnetic relays
  • Solid State Relays
  • Hybrid Relays
  • thermal relays
  • Reed Relays

Electromagnetic Relays

These relays are built with electrical, magnetic tools, and mechanical, and have an operating coil and mechanical contacts. So, when the coil gets operated by a  supply system then mechanical contacts get opened or closed. The kind of providers can be AC or DC.

Electromagnetic Relays

Solid State Relays

Solid State uses solid-state tools to act the switching operation without moving any parts. Because the control energy needed is very low compared with the output power to be controlled by these relays that result in the power gain is higher when compared to the electromagnetic relays. These are of different kinds: reed relay coupled SSR,photo-coupled SSR, transformer coupled SSR, and so on.

Hybrid Relay

These relays contain electromagnetic relays and electronic tools. Generally, the input part contains the electronic circuitry which acts as rectification and the other control functions, and the output part involves electromagnetic.

Thermal Relay

These relays are doing increase the ambient temperature from the limit, and direct the contacts to switch from one position to other. These are basically used in motor defense and consist of bimetallic elements such as temperature sensors as well as control elements. Thermal overload relays are the best example of these relays.

Reed Relay

Reed Relays consist of a set of magnetic strips which is closed within a glass tube. This reed operates as both an armature and a contact blade. The magnetic field applied to the coil is folded around this tube which makes these reeds motion so that switching work acts.

Relays are also available with different pin configurations like three-pin, four-pin, and five-pin relays. Switching contacts can be DPDT, DPST, SPDT, and SPST types. Some of the relays are commonly open (NO) kind and the others are commonly closed (NC) kinds.

DC vs AC Relays:

Working of Relay:

Applications of Relay: