What does a relay in a car do?

Question

I understand what fuses are, but I want to know what relays do.

Answer 1

A relay is a switch operated by current. The starter solenoid is an example of that, thus the heavy starter current doesn't have to be switched by the ignition switch.

Answer 2

a relay is a way of switching a big load by using a little amount of power . inside the relay is an electromagnet , when the small current (from the ignition switch) powers the relay , the electromagnet pulls a large set of contacts together so the starter can draw its power . it would be costly and scary if we had to switch the 200 or more amps the starter draws directly ,so we use a relay , they are also found in the headlamp circuits , air conditioning ,etc. hopes this helps

Answer 3

Let's say for example you need to switch on your off road driving lights, which at the moment of coming on may draw 24 amps of power. It you just had a switch, it would have to be a switch capable of handling more than that load, typically twice as much, so you would have a very big 50 amp switch. But you can also use a relay capable of handling that draw and control it with a very small trigger voltage to switch it over.

Answer 4

relays work like a breaker in that it directs the electric to a certain area of the car or motor, if for some reason the fuse would fail to break the relay is the next step in the system to protect that particular system from damage these are usually on multi-circuit systems where the main fuse controls more then one system.

Answer 5

you activate a switch to close the relay that allow power to operate what you want this cuts down on big wires that cost more so end result is cost effecientcy and less weight.