Why is my LM317 current limiter circuit not working?

Submitted by bokeb on

Noob here, but attempting to build a current limiter with a LM317 for use with a power supply to give constant current.

I have placed an extra potentiometer (the white one) to simulate changing load conditions - but when I adjust it, I am getting changing amperage - which if the LM317 was working correctly, I'm pretty sure it should not.

For testing purposes, I have not placed the R1 resistor, or connected the third leg of the R2 potentiometer (don't think either of those are needed?)

What am I doing wrong?

circuit1.jpg

circuit2.jpg

circuit3.jpg

circuit4.jpg

LM317 current limiter.jpeg

 

You need the R1. Moving the potentiometer to the end will short the Adjust leg with output.

  Joined February 12, 2018      696
Monday at 02:11 PM