What is the Purpose Of a Relay in a Car: The Ultimate Guide

What Is The Purpose Of A Relay In A Car

A relay is an electrical switch that opens and closes circuits. It is used to control a circuit with a small amount of current by using a larger amount of current. A car relay is used to control the electrical current in the car’s engine. It is typically used to control a high-powered circuit such as a car’s headlight circuit.

If you’re wondering what the purpose of a relay is in a car, read on to find out. We’ll explain what it does and how it works.

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What Is The Purpose Of A Relay In A Car

4 Pin Relay Wiring Diagram
4 Pin Relay Wiring Diagram

The automotive relay has many different purposes depending on the work needed. Here are the purposes and functions of an automotive relay.

1. Reliability Of A Component

The purpose of a relay is to increase the efficiency of a component by providing the proper amount of current. It also allows the component to function at a peak performance level.

2. Reduces Voltage Drop

Some circuits take a long distance to operate like a car headlamp or air conditioning system, which takes a few meter wire distances to operate from the dashboard to the engine compartment. And also we know that the longer the wire distance, the more resistance it has.

Hence, causes a high voltage drop and the component will not function in a fully excellent way. So, by using a relay we reduce the voltage drop.

3. Handles High Amperage Circuit

One great use of a relay is to handle the high current load by using a low current load. Some accessories need too much current which exceeds the capacity of the wire, causing burns to the wire. A relay’s coil circuit uses almost 0.5 amp current. In this case, if you use a relay, you will protect the circuit from overloading or overstressing the wire.

Also, a benefit of using a relay is that you will not need high current-rated cables. Hence, reduces cost and weight.

For example, high output headlamp requires a high amount of current which overloads the wire capacity. By using a relay we switch high-current circuits using a lower-current circuit. A normal relay can handle current up to 40 amp.

4. Controls Many Circuits With Single Relay

Central Lock Door Actuator
Central Lock Door Actuator

The function of the relay is also to control multiple circuits with one relay. A single relay’s trigger will activate one or several higher current circuits.

These circuits do multiple functions at the same time without using a bunch of relays and wires. A good example is a car control locking system. A single trigger result in all door locks locking or unlocking simultaneously.

5. Allows Circuit For Proper Fuse

Another good function of using a relay is allowing you to use a separate and proper fuse for each circuit.

6. Does Logic Functions

One of the relay’s functions is to perform logic functions. Relays are used for momentary input, time base function, and doing alternative work (like flushing alternative left or right lights). Some examples of logic functions in a car are interior lights and the time delay operation of wiper blades.

7. Connects And Disconnects The Circuits

The purpose of the relay is to isolate or connect an electrical circuit. When the relay is open, the circuit is broken and no current can flow. When the relay is closed, the circuit is complete, and the current can flow.

Related Post: Normally Open Vs Normally Closed Contact Relay, Diagrams

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