Can someone give a quick explanation on using relays when tapping cig. lighters etc. vs. just tapping the source alone?

- What are the benefits? ...and

- How do they work?

 

Relays allows you to take a lower amperage 12VDC source (cig. lighter) and control a large amperage draw (such as a large stereo system. The Cig lighter wire would not handle a large amp draw (due to the size of wire, but it would energize a relay. And possibly connected to the contacts would be a wire direct from the battery, (a large one) and one to the your stereo (another large wire also). A relay also isolates. Hope this helps. Missed last question. A relay is a coil of wire and set/s of contacts. They can be normally open, or closed. When 12VDC is applied to the relay, the coil becomes a magnet and pulls in/or drops out a set/sets of contacts. Relays contacts are either N.O. (normally open), or N.C. (normally closed). Open contacts stops the flow of electricity, and Closed contacts allow for the flow. Energizing the coil changes the N.O. contacts to Closed. A relay starts your car when you turn it to "Start". A small wire, but large wire is needed for the load of starting the car, so a relay is used. Hope this helps.