electrolysis?
power source
Using a 12v 600ma source is allowing 12 volts and 600 amps of power. If the device requires a 12v 500ma source, the larger source is acceptable. Please note that it will only be drawing on 500ma of the available 600ma.
vagina power!
A power supply that is designed to be outside the case of the computer. Most laptop computers use an external power supply rather than an internal one to reduce size and weight while the laptop runs on battery power.
Hydel Power Plant
the need for devices to function without an external power source
The power source is the expansion of the working fluid in turn producing thrust.
Active transducers are those which require electric current (a source of energy) for working, while passive transducers are those which does not need an external source. Passive transducers directly produce electric signals without an external energy source.
requires high pressure
A passive prosthesis apex :)
They don't require an external power source.
battery
A: it requires a source of power only if it has to perform any usage
Its power source is not turned on or it requires repairing.
Perpetual Motion Machine
The typical automotive alternator requires power to function.
An ignition coil requires external electrical power. A magneto requires only mechanical power to create an ignition spark. If an engine HAS no electrical power (lawnmower, tiller, chain saw) then a coil would not function.