I read that I can hook up a current sensing resitor up to a op amp in order to limit the amount of current flowing through the fet in my constant current load project? ??? Is this correct????







Thanks
Jason SR

 

As long as I = E / R is a limit you can live with that sounds fine to me.

 

A current sensing resistor or shunt is usually used as a convenient way for converting voltage to current for measurement purposes. If, for instance, you select the value of the shunt to be 1 Ohm, then from Ohm's law:-

I = V/R
I = V/1 or I = V

So by measuring the voltage across the shunt, you have instantly deduced the current, since they are the same!

HTH Steve.

 

All constant current sources must have some sort of sense sense element. This is most often a resistor. Hint https://www.google.com/search?q=LM317+constant+current+source

 

What circuit are you using to control the current?

 

This is the OP's project thread, Post #8 has a schematic.

 

I read that I can hook up a current sensing resitor up to a op amp in order to limit the amount of current flowing through the fet in my constant current load project

Like this:

 

You can make your own precision shunt using constantan or manganin wire, which has zero TC and is available in various thicknesses.

 

Thanks guy for the help and info but I have decided to go a different route..
My design for the constant current load is almost done and I am very proud of it and will update the thread later info...




Thanks
Jason SR