Hi,

I need to test a constant current circuit up to 20A.
My real load is a light diode with about 2.5V forward voltage and I don't want to use it to test the circuit as it is pretty expensive.
What would you recommend for a dummy load?

 

eight (1) ohm 10 watt resistors in parallel.

 

eight (1) ohm 10 watt resistors in parallel.

In a tub of motor oil or distilled water.

 

Five headlights in parallel will draw about 20A at 12V. No oil bath needed. And you can land airplanes.

 

C'mon guys, 80 watts worth of resistors on a 50 watt supply isn't going to need liquid cooling.

and 12 volt light bulbs don't work very well on 2.5 volts.

 

...and 12 volt light bulbs don't work very well on 2.5 volts.

Haha, yeah, missed that. I even double checked for the OP's voltage but that didn't register. I gave blood last night. Let's blame that.

The resistors will work just fine. Just let them breathe.

 

and very heavy interconnects (wiering between resistors and source.)