# What is Relay? What are it's Types?

**URL:** <https://forumautomation.com/t/what-is-relay-what-are-its-types/12481>\
**Category:** Uncategorized\
**Created:** [August 23, 2024, 3:18pm UTC](https://forumautomation.com/t/what-is-relay-what-are-its-types/12481 "2024-08-23T15:18:33Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Rabert](https://forumautomation.com/user_avatar/forumautomation.com/rabert/32/6784_2.png) [@Rabert](https://forumautomation.com/u/Rabert)\
**Post date:** [August 23, 2024, 3:18pm UTC](https://forumautomation.com/t/what-is-relay-what-are-its-types/12481/1 "2024-08-23T15:18:34Z")

</div>

## What is a Relay?

A relay is a sensor that detects abnormal signals and sends them to the circuit breaker. Hence the circuit breaker (trip).

 ![image](https://cdn.forumautomation.com/original/2X/f/fb361ca0ad5941827c0051ba6b5cab07ae6e4b24.jpeg)

A relay is an electrical switch that opens (or) closes a circuit when a certain condition is fulfilled. It is primarily an equipment that detects changes in physical properties. Examples include voltage, current, temperature, and pressure.

## Types of Relays

1. Electromechanical relays (EMR)

2. Solid state relay (SSR)

3. Hybrid Relay

4. Smart Relay

## Functions of Relays

Features include

- Overcurrent and undervoltage safety.
- Frequency protection
- Distance protection
- Directional protection