Hello,
In my project, I need to use a current source delivring 40 outputs of 100mA each for 40 parallel wires. I know I can't find such device in the net (with this huge output number).
First I thought to use a single supply with a current divider, but the problem is, wires could be cutted during working, meaning current in other working wires will arise and exceed 100mA.
Does anyone know a multi-output commercial device ( current source )?
If not, do you think that I can build my own product if I gather 40 device of this ?
Thanks

A "USB Programmable" 48 Channel Constant Current Source @ 0 - 100 ma per channel ...
https://www.hypres.com/products/current-source/

 

How about something like this? The V1 supply voltage doesn't matter much - you could use a car battery. The transistor will keep about 100mA flowing in the wire based on the value of the V2 voltage and the value of R1. The voltage on top of R1 will be a fairly steady 2.5V as long as the wire is not open or shorted. R1 needs to be rated to I^2•R = 0.01•25 = 0.25W. Use at least a 0.5W rating for safety.

Transistors and resistors are both available in array packages, so you'd need only about 4-5 of each.

This would be a lot easier if you could reduce the test current to 10mA. That would allow using an LED for quick visual feedback in series with the wire and would eliminate the issues of power ratings for the resistor and transistor.

Oh, and I put the voltage-out in the wrong spot. It should be at the bottom of R1, on top the wire.

One more thing, have you considered multiplexing?

View attachment 172430

Hi Wayneh,
Thank you for this solution, but I think it's much easier to use led driver module, it's compact and easy to use;
Thank you so much for your assistance.

 

A "USB Programmable" 48 Channel Constant Current Source @ 0 - 100 ma per channel ...
https://www.hypres.com/products/current-source/

Mvas,
You just made my day !
Thank you so much, you made my work so much easier!