I know that a power supply typically
rectfies (converts AC to DC) and tranforms (converts 12v to 6v)
but at that point what is the difference for the way it outputs
5 amps at 6 volts and a charger 5 amps at 6 volts.

Are you saying the powersupply has a circuit that keeps (regulates) the volatge to remain a constant 6 volts ?

While the typical NIMH NICAD charger has a circuit that makes sure its ouput is 5 amps?

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