How A 12 Volt Relay Works

Most 12 volt relays operate accessories in a motor vehicle.

How a 12 volt relay works.

What is a relay. 3 pin 4 pin 5 pin iso standardized relays iso relays were designed to try and standardize relay connections making it easier to test and design systems. Applying a small amount as low as 2 amps of current to the relay coil closes contacts to feed power to an accessory that requires more current to operate usually over 20 amps. Gday guys and gals.

Understanding how the relay works will help with diagnosis and modifications to vehicle systems. I apologize in advance for being so boring and repeating myself cou. Two wires to the. Although there are various relay designs the ones most commonly found in low voltage auto and marine applications are electro mechanical relays that work by activating an electromagnet to pull a set of contacts to make or break a circuit.

Relays are either electromechanical relays or solid state relays. Iso relays are currently used by almost all automotive manufacturers today. With solid state relays ssr there are no contacts and switching is totally electronic. To wire an automotive relay make at least four connections.

In electromechanical relays emr contacts are opened or closed by a magnetic force. When the relay is energized on pins 3 and 5 have continuity. I firstly describe how the rela. The decision to use electromechanical or solid state relays depends on an application s electrical requirements cost constraints and life expectancy.

A relay is essentially a switch that is operated electrically rather than mechanically. What happens inside a relay isn t magic but it is important. In this video i give you a thorough look at how a 12v automotive relay works and also how to wire one up. A normally open relay will switch power on for a circuit when the coil is activated.

Here s another video explaining the what s how s and why s about our friend the relay.