Recommendations needed for programmable DC supply and logging DMM (< 1.5V, < 1A)

[ElectroGuy505]

Hey all,

I am currently doing a project of which the setup will consist of two electrochemical cells. On cell 1 a constant DC voltage needs to be applied and on cell 2 the emf / DC voltage across the cell needs to be measured. For a schematic, see the picture that I attached. The voltages will range from 0 to about 1.5 V. The currents will be relatively low; way below 1 A.

Some requirements I have are:
- A programmable applied DC voltage for cell 1
- Record the measured DC voltage over time for cell 2 (up to 10's of hours, sampling every couple minutes)

So far I have decided that I will use a DC power supply for cell 1 and a digital multimeter (DMM) for cell 2. Could anyone give me options/recommendations in different price categories for the DC power supply and DMM that would be useful in this case?

Furthermore, would remote sense be needed for the DC supply?

Thanks in advance,

Koen

 

[JonSea]

One option would be to use **broken link removed**. You supply a grater DC voltage and current than you need from something like a laptop power supply, and they regulate the voltage to the desired level. Accurate voltage and current are shown on the display.

But if you add the optional USB/Bluetooth interface, you can control and get the readings from a computer. It wouldn't be much work to automate control and data logging.

 

[Reloadron]

The need for sense will depend mostly on the lead length between your supply and load as well as the wire gauge used. My guess would be no, sense won't be needed.

Finding a 0 to 1.5 or lets say 0 to 5 VDC supply won't be easy depending on your budget? This is especially true if you want a programmable supply, this is for your Cell #1 as you mention:

- A programmable applied DC voltage for cell 1

If you want programmable you need to define the resolution you need and the type interface you need or want?

As to your cell #2 again the resolution and interface? When you log data or collect data it needs to go somewhere?

What you are wanting to do is very doable but with the voltages you mention along with the uncertainties (accuracy) and resolutions it may not be inexpensive.

I see JonSea posted and I like his solution if it will give you what you want.

Ron

 

[ElectroGuy505]

Thanks for the recommendations Jonsea and Reloadron. The lead length is indeed not too long, so I guess remote sense is not per se needed. The resolution might indeed be a problem; I would like at least a resolution of 2 to 5 mV. I am very new with this all. I know that there are various interfaces like USB, RS232, and GPIB. What would you recommend if I want to control and collect data on a PC?

 

[JonSea]

The resolution on the power supplies I posted is about 1mV. They can be controlled and the voltage/current read out via USB.

You'll probably need to write some software to control the power supplies. Labview may have drivers to control them.

If you need greater resolution for voltage and current, there are some great power monitor chips like the TI TMP512/TMP513. These chips can also monitor temperature with remote diodes if that's a consideration.