Energy Transfer In an Electronic Circuit

Most people believe that energy in an electronic circuit is transported by the wires. However in both AC and DC circuits energy is transported by the fields between the wires. Here is an example to put this proposal in perspective…

100,000 VOLTS DC connected to a load of 100,000 OHMS through a long pair of wires that have a diameter of 1mm.

Using ohms law we can conclude that the current in the wires will be 1 AMP.

1 AMP through a wire with 100,000 VOLTS applied, delivers 100,000 WATTS into the load, which is 134 HORSEPOWER.

Thats 134 HORSEPOWER going through a wire with a diameter of 1mm. This intuitively implies that the energy is being transferred in some other way, other than just the wire.

Wires are rated with how many amps they can deliver, not voltage. The voltage rating is irrelevant until the voltage is high enough to cause arcing between the two parallel wires, in which case the wires can be spread farther apart or by adding insulation between the wires.

Modern phone chargers use 20 to 50 VOLTS DC at 3 to 5 AMPS. However, there is no practical limit to the voltage that can be applied to such a cable system, as long as there is no arcing between conductors.

Imagine a phone charger cable carrying 5 AMPS at 1,000 VOLTS DC… that's 5,000 WATTS… which is 7 HORSEPOWER. That means you can use a phone charger cable to power a lawn mower.

For more, see “Energy Flux” and “Poynting Vector”