Purchased a 'used' DC power supply.. I am using a pen plater.
Plating gold on to silver. Not sure which terminal is the plus and
negative (no mark).
What you need is a solution of an acid/alkali indicator, such as
litmus, even red cabbage or beetroot liquid would do. Add a pinch of
salt Epsom salt would be better - and place the two bare wires in
the liquid. The liquid around the negative wire will turn blue, and
it will stay red around the positive.
plating at 9 (or any other voltage) volts, the amp meter does
register, Is this usual???
The amount of current flowing - amps - in any circuit depends on the
total resistance of the circuit. If the power supply has an inbuilt
high resistance then it will not supply high current. The amount of
metal deposited from a plating solution per unit of time depends
upon amps times volts - watts, or work done in metal deposition; if
the wattage is low the deposit of metal will be low and poor.
Many DC power supply units are designed for use with electronic
devices which use very little power- current - and so the internal
resistance of the supply is high. Perhaps that is what you have.
Actually the easiest way to check the polarity is to use an external
meter, but you probably don’t have one. Another point is that your
plating solution may be old, or lacking in gold.
Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ