On 13 Feb 2011 22:53:53 GMT, "DoN. Nichols"
wrote:



I designed and built an adjustable constant-current supply. It can be
set anywhere from 10 mA to 1.5 amps -- most of my projects are small
enough to easily fit in a 2-gallon bucket. Before I made that supply
I used a variac, battery charger and ammeter.

Out of curiosity -- what is the voltage compliance of this CC
power supply? Likely one of the lab supplies that I have would do for
the task for reasonable sized objets.

Enjoy,
DoN.

It's quite high, probably dynamic Z of tens of megohms, but that's
just how it turned out. It wouldn't need to be that high for plating.
I built it because I got tired of replacing the fuse in my multimeter
every time something shorted out in the bucket. It's just an LM324
opamp feedback loop comparing the voltage on an emitter (or source)
resistor to the voltage on a pot driven by a voltage reference.

Zinc only needs about 30 mA per square inch so a couple of amps is
plenty for anything that'll fit in a 2-gallon bucket.

A lab supply in constant current mode would work fine. I didn't want
to move my lab supply back and forth. This supply is about the size
of a recipe box and is bolted to the plating cart.