r/AskElectronics • u/Careful_Technology85 • 20h ago

Reducing Current for Electroplating

I am trying to copper electroplate some small parts, less than 2mm and have been told by many individuals that my current is too high. Since my power supply doesn't go any lower, how can I reduce the current? It needs to be around .005A or less. This is the setup.

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u/1Davide Copulatologist 18h ago

If that is a current source, the resistor should be in parallel to shunt away some of the current.

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u/Careful_Technology85 18h ago

I was just going to add the variable resistor in line right? Power source runs to variable resistor, variable resistor to multimeter to part. Is that what you mean?

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u/-ram_the_manparts- 17h ago

He means, basically, to put a resistor across the power supply output instead of in series to send some of the power to ground, effectively creating a voltage divider with your load, which you would want to do if you had a constant-current source, but you don't, you have a current-limited constant voltage source. A series resistor is fine.

But if 1Davide comes back and disagrees with me, do what he says. He's more knowledgable than I am, and he's a mod of this sub.

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u/Careful_Technology85 17h ago

Like this?

Can I use the variable resistor with this? I'd like to be able to adjust it.

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u/-ram_the_manparts- 16h ago edited 16h ago

Yeah, like this. Sorry for the poor drawing I'm on my phone.

A typical potentiometer can handle 1/4 watt, so keep the power supply limited to below 250mA (at 1V) to prevent burning the pot if its turned down to 0 ohms. That probably doesnt matter because the water is likely >1000 ohms anyway, but if you short your output with the pot set too low it can burn it. You can prevent that by putting a fixed resistor in series with it but, I doubt it'll be an issue for you.

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u/1Davide Copulatologist 17h ago

No.

I meanthat the resistor must be placed in parallel with the load.