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BrianG · 02.23.2010, 12:05 AM

It would be simpler to use a LM317T vreg with a pass transistor, configured as a constant current source. The higher the voltage regulator rating, the more voltage headroom he is going to need.

You could also build a CC source using three diodes, a resistor, and a Darlington NPN transistor. This would require even less voltage headroom, but would also take a bit more design to do properly.

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BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	02.23.2010, 12:05 AM It would be simpler to use a LM317T vreg with a pass transistor, configured as a constant current source. The higher the voltage regulator rating, the more voltage headroom he is going to need. You could also build a CC source using three diodes, a resistor, and a Darlington NPN transistor. This would require even less voltage headroom, but would also take a bit more design to do properly.