When is electrical energy transferred?

Answer 1

Through conduction and induction. Electrons stay generally in the same place while the energy is imparted through the wire. Resistors and capacitors deal with electricity in their own ways. Caps store and discharge energy while resistors can set voltage levels and current flow. In a transformer, two coils on a metal frame can impart their energy on one another, actually transfer it. This happens through the magnetic fields described by Faraday. The active elements in electronics are numerous but few effect the flow of electricity more than the modern transistor. It has almost totally supplanted the tube as a control device. The transistor can control large amounts of current in its' different iterations, the SCR, Triac, FET, IGT, etc.

Answer 2

Electric current is the flow of electrons. Electrical energy is transferred round a circuit by the flow current. The flow can be measured in amps using an ammeter in the circuit.

Answer

The above answer is obviously incorrect, because it cannot explain how a.c. is able to transfer energy or how the slow-moving electrons in d.c. (millimetres per hour) would ever be able to transfer energy from the supply to the load. The correct answer is that energy is probably transferred by a combination of the electric and magnetic fields, known as the 'Poynting field', which is external to the wires.

Answer 3

In a pure D.C. circuit, electricity, a.k.a. {current} flows from the negative side of the power source, through the load, and back to the source of power. In an A.C. circuit the negative and positive points of the power source oscillate 60 times per second.

Answer 4

All the time. It has to be generated at the time of use because storage is very difficult, for example a car batterycan store only about half a kilowatt-hour.