> You could use an LM3875, I think you could get it to work in > single-supply fashion There is an example in the datasheet. If the VA is too much for a lone opamp then something like that amp or an opamp + driver stage will be needed. The best thing to do now would be to take a variable PSU to the dynamometer and measure the input current across the range -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist