Hi, could someone explain how energy and voltage operate in an electrical circuit. I'm really confused because I was reading a book on misconceptions in electric circuits which said that energy is not associated with the charges in a circuit. It goes on to say that if it did then you would have to wait for electrons from the battery to arrive at the the load. It says that a common analogy of voltage and energy is using freight carts. If you had a 6V battery then the battery gives the carts 6J of energy and the carts take them and drop them off at the load and then they go back to the battery to get re-filled. It says that this analogy is completely wrong and misleading. How should you view potential difference then? If the potential difference across a bulb is 6V then doesn't this mean that each coulomb of charge loses 6J of energy going across the bulb? But then how does this apply to a.c. because charge makes no net movement in any direction, they just vibrate back and forth due to the electric field? So what then does 6 joules per coulomb actually mean?