Passage: All electric circuits have at least two parts: a voltage source and a conductor. They may have other parts as well, such as light bulbs and switches, as in the simple circuit seen in the Figure below . To see an animation of a circuit like this one, go to: http://www. rkm. com. au/animations/animation-electrical-circuit. html. Answer: electric circuits
A voltage source and a conductor are common to all what?