What Does A Relay Switch Do In A Car

A relay is an electrically operated switch it consists of a set of input terminals for a single or multiple control signals and a set of operating contact terminals the switch may have any number of contacts in multiple contact forms such as make contacts break contacts or combinations thereof.

What does a relay switch do in a car. Car relays can come in all sorts of shapes and sized and they all look very different but have similar functions. Relays in general are used to enable a low amperage circuit to switch on or off a higher amperage circuit like turning on your headlights. By putting an end of an alligator clip to a grounded spot you will then touch a wire of the relay switch with a multimeter. Here are two simple animations illustrating how relays use one circuit to switch on a second circuit.

When power flows through the first circuit 1 it activates the electromagnet brown generating a magnetic field blue that attracts a contact red and activates the second circuit 2. If the component still does not work it is faulty. Another important function of the relay is quick switching off 0 05sec max. A very basic relay has two circuits.

An input or control circuit and an out circuit. Record the measured voltage and if it is not the right amount then your relay switch is working poorly. To switch on a 12v 60 100 watt halogen lamp a typical 12v relay allows a voltage drop of only 0 02v and the coil current is only 2 milliamps. Relays are used where it is necessary to control a circuit by an independent low power signal.

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 for example you might want the electromagnet to energize using 5 volts and 50 milliamps 250 milliwatts while the armature can support 120v ac at 2. Remove your car s dashboard as this is the main site of the relay switches and then turn your car on. If a component that is fed with electricity through a relay see how car electrical systems work terminal of the battery to the feed terminal on the component thereby bypassing the relay and supply wiring. Automotive relays of all shapes and sizes can be found in just about every car truck and even boats.

It allows small currents to control accessories that require large currents and thus eliminating the need for heavy switches and. If it works then the supply is faulty and the fault will be in the relay or the connections to it. Whenever you operate a switch to an accessory in your car that carries a lot of current such as the lights wipers or horn you run a small amount of current through a relay which in turn closes contacts to operate the accessory.