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# Electronics/Electricity and electrophoresis

Question
First thing first, I know the bare minimum about electricity. That being said here is my question. I want to take a 12V car battery and experiment with electrophoresis. I want to be able to control the amount of amps, as low as milli amps, without changing voltage. How do I do this?

https://en.wikipedia.org/wiki/Electrophoresis

which may give you some deeper background into the science of particle separation.

You cannot, according to ohms law (voltage = current times resistance) you cannot change the current whilst keeping the voltage constant without changing the resistance.

In your case the resistance is the bath or liquid for which current is flowing.

I think what you want to do is put a rheostat in series with the battery which would increase the resistance and hence reduce the current; however, voltage at the bath or gel would reduce.

I suggest you start with a rheostat of a few hundred ohms.

https://www.amazon.com/b?node=306811011

Let me know if you need more.

Electronics

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#### ZZ

##### Expertise

Electronics questions about AC, DC and digital theory.

##### Experience

Graduate electrical engineer with over 40 years in electronic design, manufacturing, project organization and patent review. Experience in fields of industrial and consumer electronics (audio, video, acoustics, etc.)

Organizations
IEEE (Institute of Electrical and Electronics Engineers); Senior Life member AES (Audio Engineering Society), Fellow Life member

Education/Credentials
BSEE University of North Dakota