How electricity is transmitted over a contact since metal to metal contact surface is really small?

Question

How electricity is transmitted over a contact since metal to metal contact surface is really small?

In: 1

Answer 1

The contact area is big enough to transmit electricity. Also very short distances can easily be jumped over through ionization (roughly one milimeter per kilovolt)

But yes, contacts do constrain current into a smaller area, especially when dirty. That’s usually not a big problem, but can destroy the surface after many switching cycles (because every time a little spark can evaporate a little material)