brushes are ...?

Question

what are brushes or (spring loaded contacts) and How do they work?

http://en.wikipedia.org/wiki/Brush_(electric)

<-- it says what they do not enough on what they are physically.

Appreciated.

Answer 1

Brushes are electrical conductors that maintain electrical contact between a stationary thing and a rotating thing. They are called brushes because the first designs looked like a paint brush made with fine copper wires. Electric motors and electrical generators have brushes. Today, many of these brushes are made of graphite or Cu-graphite composites so they conduct electricity and they do not wear away as quickly as Cu wire. Electrical contacts are a different thing. Electrical contacts are, typically, for "make and break" electrical connections. Your light switches in your house and in your car are make/break connects. The plugs on your TV and computer cables are make/break connections. The technology trick is that when the electrical circuit is made or broken, there is an electric arc. Electric arcs are hot enough they they can melt metal. Hopefully the amount of metal that melts is very tiny, microscopic points on the surfaces of the actual contact pads.

I hope this helps.