Need current source 0-20mA schematic

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mrcube_ns

Joined: 10 Apr 2002
Posts: 429
Helped: 11
Location: Dark side of the Moon

30 Mar 2006 11:06 current source schematic

Hello friends,

I tried to search for schematic on this forum but I wasn't find any schematic i got over 7000 matches.

Can someone post me some, good one, schematic for current source (or link to it), (I want to use precise (10 or more round) potentiometer to change current), with transistors or OP amp or you tell me.

Thank you in advance.

Mr.Cube

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30 Mar 2006 11:06 Ads

IanP

Joined: 05 Oct 2004
Posts: 6490
Helped: 1542
Location: West Coast

30 Mar 2006 11:48 constant current source schematic

One possible option is to use an opamp in voltage-to-current configuration where the output current I = Vin/Rsense .. drawback: sinking current ..
http://www.ecircuitcenter.com/Circuits/curr_src1/curr_src1.htm

However, instead of trying to reinvent a wheel why not to use off-the-shelf solution ..
Its name is XTR110 and your multiturn potentiometer can be connected between 5V reference-ground and pin 5 (in 0-5V to 0-20mA configuration) ..
http://focus.ti.com/docs/prod/folders/print/xtr110.html
( In fact you can copy its internal configuration and build the whole circuit using standard opamps) ..

Regards,
IanP

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