Chris Jones wrote:
Fred Bloggs wrote:

A batt charger is a good thing for regular use, but as a one off its
not needed. A psu and light bulb will do for a one off.


Nice...nice way to convert a 65W job into 8KW that is.

If you start with a 3.3V ATX power supply (or half a dozen of them - out of
a dumpster, if cost is a problem), then you don't have to drop much
voltage. A light bulb would present too much resistance so some other kind
of resistor would be needed - perhaps some iron fencing wire on a suitable
heat-proof support- or a linear voltage regulator if this is to be used
repeatedly.

Chris

Start with a 6v bulb, filament bulbs have an 8:1 resistance ratio
between hot & cold, it runs far below rated power


NT