Hi there,

i'm trying to develop a current source with the voltage regulator i've already had in my collection. It's the BA033ST (https://nl.mouser.com/datasheet/2/348/rohm_BA00ST-SFP_Series-1201674.pdf). Somehow i'm fucking this up and shorted the circuit a few times. What i'm willing to do is to develop a regulated constant current source. My plan was to do this with a variable resistor which ranges from 0 to 1000 ohms. In the image i will add as an attachment, you can see how i thought the circuit should be set up. Please correct me what i'm doing wrong. I'm getting really weird values and short circuits a lot.

The DUT which i want to put a constant current on will have a wide range of resistance.

TIA

 

X

 

Your regulator is a Fixed 3.3V type, so you cant use it as a Variable one, pin 5 is the reference feedback input 1.25V, ..

The BA00ST is the variable one.
you're better off using a LM317 as a Constant Current source,
For 100 to 500mA you will need a 2.5 to 12.5 ohms preset at 1W min.