# Current density sensors

1. Jun 9, 2017

### maconga

Hi all, dont know if this is the appropiated place to search. Im trying to find a supplier for a current density probe (Hall sensor or similar) to measure the current density in a tank where an aluminum foil is treated to form electrolitical capacitor.
Im searching for this in Europe and USA but cant find the supplier.
Could someone guide me please on this topic?

2. Jun 9, 2017

### Staff: Mentor

Welcome to the PF.

Can you give more details about the setup, and maybe post a couple pictures? (Use the UPLOAD button to attach pictures)

Is this a DC current density, or AC too? If AC is involved, what frequency range?

3. Jun 12, 2017

### maconga

Hi Berkeman, thanks very much for replying,
The idea is to measure the density of current flowing in the solution during the process between foil and cathode by introducing a Hall probe (dont know why a Hall probe and not just an ammeter) into the solution.
We treat an etched aluminum foil in a few tanks with solution where we apply certain voltage.
I need to know which is the current density in the solution so we can know the current on the surface foil.
Many years ago we they used to work with Hall probes.
What we have in the tanks is a DC current density. The electricity from the transformers is AC but it’s converted into DC when it’s supplied to the machines.
As you can notice Im not a specialist at all in this field, but I was given this topic and cant find any supplier :/

4. Jun 12, 2017

### Staff: Mentor

Can you just measure the overall flow and divide by the area? Or is the current density different in different areas of the tank, and that's what you want to map out?

I think you would use the Hall sensor because it would disturb the currents to try to use any conductive ammeter arrangement.

I'm not sure how to waterproof it, but I think the basic idea would be to use a Hall current sensor probe like the one below, and have a short straw or similar through the center hole to let the current flow through to be measured...

http://www.alliedelec.com/images/products/Small/70282708.jpg

5. Jun 12, 2017

### jim hardy

I think in electroplating current density refers to amps per square inch of the object being plated.

Like you i can only find references to companies that don't seem to exist anymore.

https://www.openfos.com/supply/2509245-INDUSTRIAL-INSTRUMENTS-in-Newport-News-VA/
http://www.ebay.com/itm/PLATING-CURRENT-DENSITY-MICRO-OHM-METER-/231205023788

Here's an old patent for such a meter, based on ohm's law.
US003347770

http://pdfpiw.uspto.gov/.piw?PageNu...BPN/A000000%26RS=PN/3347770%2BOR%2BPN/A000000

6. Jun 12, 2017

### marcusl

I once visited an industrial electroplating concern who used rectangular tanks with planar electrodes on opposite sides, so as to produce uniform current density J. This makes sense, since any non-uniform J would deposit a film that varies with position. Accordingly, berkeman's suggesting would work well.