# DC Power Supply

Discussion in 'The Projects Forum' started by clear856, Mar 1, 2011.

1. ### clear856 Thread Starter New Member

Mar 1, 2011
2
0
Hello

I am conducting research in which I electro etch materials. For one technique I need a power supply that can output a constant current into multiple channels. However, all channels come in contact with the same etching bath and lead to only one cathode.

I was wondering if there is a way to supply a constant current to all channels even though they all come in electrical contact with one another when their respective anodes are lowered into an electrolytic bath.

How would such a power supply be designed?
I am not too familiar with these sorts of things, and the electronics shop manager in charge of making the power supply is not exactly sure how to put one together for this application.

Any help would be appreciated

Cheers

2. ### wayneh Expert

Sep 9, 2010
13,624
4,416
Multiple channels is not a problem - you'll need a control on each - but how much current are you looking for? And what sort of supply do you have?

And welcome to the AAC forum!

3. ### Wendy Moderator

Mar 24, 2008
21,012
2,745
Do you want each channel to be a separate current, or one constant current.

There are many ways to do this, most are pretty good, but we need the magnitude of the current (what wayneh said).

4. ### clear856 Thread Starter New Member

Mar 1, 2011
2
0
each channel should have a constant current of up to 100 mA

5. ### Wendy Moderator

Mar 24, 2008
21,012
2,745
And the minimum? 0 is doable, but setting it to a number makes it a bit easier.

6. ### Wendy Moderator

Mar 24, 2008
21,012
2,745
BTW, here is a simple one, I assume you need a source.

Up R1 to 10Ω, it will be 0 - 600 ma. If R1 is 56Ω it will be 0 - 110ma.

Max current = 0.6V / R1

Last edited: Mar 4, 2011
7. ### wayneh Expert

Sep 9, 2010
13,624
4,416
Here's a more elaborate version. You may need to experiment a bit with the shunt resistor (shown as 1 ohm) and the current limiting resistor, if needed. Also, you could certainly use a single power supply (at 12v, eliminating the 5v reference) but it would need to be regulated at some voltage to act as voltage reference.