Thanks Sean. That has crossed my mind as well. However, building a very accurate 10 Amp current source is not that easy and consumes too much engineering time. Buying a very accurate 10 Amp current source might cost much as well. I haven't found any yet, only a 100mA max. unit from Keithley (6220). I am waiting for a quote on this unit, but I guess it will not be cheap. Daniel... ----- Original Message ----- From: "Sean Breheny" To: "Microcontroller discussion list - Public." Sent: Tuesday, January 16, 2007 7:46 PM Subject: Re: [EE] Looking for a micro Ohm meter > Hi Daniel, > > What about simply making or buying a very accurate current source (for > say 10 amps) and then using a regular multimeter to measure the > voltage across the shunt? It would be 1mV at 10 amps. You could even > go higher in current if needed to get a large enough signal. > > I've used this technique in the past to measure low resistance values. > > Sean > > > On 1/16/07, Daniel Schouten wrote: >> Hi all, >> >> I am looking for an instrument to accurately measure a resistance of 100 >> uOhms. This instrument will be used in a setup to trim large current >> shunts from 100uOhms -5% to 100 uOhms - 0.25%. Budget is < 2k USD. I have >> seen several options (Agilent, Keithley), but most are too expensive or >> too >> versatile (I only need to measure low Ohmic values). >> >> Are there any relativily simple but accurate instruments on the market to >> perform this task? I have also heard of building a Wheatstone bridge, but >> this sounds a little bit too experimental for me. The measurements must >> be >> taken reliably and some volume trimming of shunts might also be involved >> in >> the near future. >> >> Thanks! >> >> Daniel... >> >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist