Erratic Current Source

Wendy

Joined Mar 24, 2008
23,415
A LM358 is capable of going near ground and may do what you want. It is very slow though, which is not good. Spikes can still make their way through. Wookie may be able to suggest another op amp that handle inputs near ground better, like the LM358. It would be better to order this part mail order via Digikey or BG Micro than make do.
 

Thread Starter

jbord39

Joined Mar 31, 2010
41
I found a few LM358's lying around and now have the circuit working!! The problem before I think had to do with my transistors instantly burning out (because of the incompatible op-amp); combined with the fact that the op-amp wasn't right for this choice.

Does anyone know what sort of spikes I could expect with this? +/-100mA is not a big deal but more than that and I could risk burning out the diode when it's already being driven close to it's maximum (around 2A).

Thanks,

John
 
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