A machine that generates more power than it uses.

[qazwart]

@gnoitall

In simplistic DC terms, resistance figures in by reducing available current and “dropping” some of the available voltage. A series resistance “drops” a portion of the voltage proportionate to its resistance compared to the overall resistance of the circuit. That voltage drop is transformed into something else. Some of a motor’s “resistance” is transformed into mechanical motion (through the magic of electromagnetism, for instance.) A transformer or other coil device generates heat (“wasted”), and may also generate mechanical energy (vibration, buzzing, etc.) A straighforward resistor just generates heat, unless you push it beyond its current or voltage limits, in which case it generates light, loud noise, or magic smoke. :eek: (That’s the voice of experience there.)

AC resistance is more complicated (and is the accurate way to model a transformer), but still works out the same in the end: voltage drop becomes some other kind of energy, whether “useful” or “wasted”.

The other side of a transformer or tesla coil is actually a different circuit, so the input voltage and output voltage are independent (different electrons). The coil arrangement induces higher voltage in the secondary coil at the expense of lower current capability, with the additional bonus that some of the energy input at the primary (input) coil side will be lost as mentioned above.

Man, apparently I didn’t sleep through just one class. I slept through the entire semester!