How A 12 Volt Relay Works

Most 12 volt relays operate accessories in a motor vehicle.

How a 12 volt relay works.

To wire an automotive relay make at least four connections. Gday guys and gals. A relay is essentially a switch that is operated electrically rather than mechanically. The decision to use electromechanical or solid state relays depends on an application s electrical requirements cost constraints and life expectancy.

With solid state relays ssr there are no contacts and switching is totally electronic. Relays are either electromechanical relays or solid state relays. 5 pin relay 5 pin relays provide 2 pins 85 86 to control the coil and 3 pins 30 87 87a which switch power between two circuits. Here s another video explaining the what s how s and why s about our friend the relay.

I firstly describe how the rela. 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. Understanding how the relay works will help with diagnosis and modifications to vehicle systems. A normally closed relay will switch power off for a circuit when the coil is activated.

When the relay is energized on pins 3 and 5 have continuity. I apologize in advance for being so boring and repeating myself cou. Iso relays are currently used by almost all automotive manufacturers today. I want to run a sim module with an arduino with a relay first relay coil 12v second relay coil 5v i want the system to start the 12 volt battery automatically when power goes off how can i operate these two relays with an adapter how can i charge the battery externally without touching the cables of the system when the battery is discharged.

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. What is a relay. 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. In electromechanical relays emr contacts are opened or closed by a magnetic force.

In this video i give you a thorough look at how a 12v automotive relay works and also how to wire one up.