Re: Adjustable Constant Current Drive
- From: "John Jardine." <john@xxxxxxxxxxxxxxxxxxxxx>
- Date: Fri, 25 Aug 2006 20:20:55 +0100
<graeme.cunningham@xxxxxxxxxxxxxx> wrote in message
news:1156420236.347910.56500@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi
I'm trying to design an adjustable constant current drive to supply a
current of 250mA.
I've been trying to use OP amps but have been running into problems as
I need to limit the supply voltage to +/- 5v
Any help would be much appreciated.
G
As Leon mentions, maybe this kind of arrangement ...
o-------------------o-------5V
| |
.-. .-.
| | | |4.7 ohm
| | | |
'-'150 ohm '-'
| |
| | PNP Darlington
.-. |< TIP ???
| |<---------------|
| | |\
'-' Pot |
| 100 ohm |
| o
|
.-. |
| | < V Special LED
| | < -
'-' |
| 220 ohm
| o
| |
| | 0-250ma
| |
o-------------------o-------0V
-
(created by AACircuit v1.28 beta 10/06/04 www.tech-chat.de)
.
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- Adjustable Constant Current Drive
- From: graeme.cunningham@xxxxxxxxxxxxxx
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