Week 9

Title of Activity

Research about Relay

Objective

• Introduction how relay work
• Relay construction
• Relay application 

Content/Procedure

Introduction

A relay is a simple electromechanical switch made up of an electromagnet and a set of contacts. Relays are found hidden in all sorts of devices. In fact, some of the first computers ever built used relays to implement Boolean gate

Construction

Relays consist from four parts :

• Electromagnet
• Armature that can be attracted by the electromagnet
• Spring
• Set of electrical contacts

Below is show simple how relay works

Relay Turn Off

Relay Turn On

  In this figure, you can see that a relay consists of two separate and completely independent circuits. The first is at the bottom and drives the electromagnet In this circuit, a switch is controlling power to the electromagnet. When the switch is on, the electromagnet is on, and it attracts the armature (blue). The armature is acting as a switch in the second circuit. When the electromagnet is energized, the armature completes the second circuit and the light is on. When the electromagnet is not energized, the spring pulls the armature away and the circuit is not complete. In that case, the light is dark.

Application

   In general, the point of a relay is to use a small amount of power in the electromagnet coming, say, from a small dashboard switch or a low power electronic circuit to move an armature that is able to switch a much larger amount of power. Relays are quite common in home appliances where there is an electronic control turning on something like a motor or light.

Relay

Result/Analysis

In this situation relay also can to be switched, plus it  are often cascaded.