Hi Marcel, I don't think that adding in an additional "real" offset current and then subtracting that off later does anything to improve the problem of percentage error near 0 Amps. This is simply the nature of the concept of percentage - there will always be some false offset (which is unaffected by whether you add in some other fixed current) and to whatever extent you do not know the value of this fixed offset, it will contribute to a percentage error which climbs to infinity near 0 current. The only way around this that I know of would be to modulate the current you are trying to measure so that you can then AC-couple the output of the sensor and get rid of any DC-offset. Sean On Wed, Aug 10, 2011 at 12:25 AM, Marcel Duchamp wrote: > One thing about sensors like this is that they exhibit errors due to > offset voltage which means that as your measured current drops toward > zero, the error goes to infinity. =A0You can possibly avoid this by alway= s > loading your circuit with a known amount of current and then subtracting > that out of the readings. =A0The other thing is to use as large of a valu= e > of sense resistor as is possible since a large measured voltage vs any > fixed offsets improves the accuracy as well. > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .