- Joined Feb 1, 2010
I need a ~2.13 Amp constant current device in order to test some batteries. I got some surplus LM317's for cheap and would like to gang them up as shown in the schematic.
I figured the 4.7 and 5.1 ohm get me 2.44 ohms and that should give me ~510 mA. Four of those get's 2.05 Amps plus one with a 10 ohm for 130 mA for a total of ~2.17 amps total. Using the formula from here http://diyaudioprojects.com/Technical/Voltage-Regulator/
The results were spectacular (if you like the smell of resistors burning). It worked fine with one but something went amiss when I ganged them up. Should this be able to work? Maybe I have some bad LM317's for $.30 each? Does tying the inputs and outputs put a possible higher voltage on the output than the input and kill the LM317?
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