Ad-hoc Correction of Error due to Input Resistance of DAQ Units

To measure the bipolar voltage at a unipolar power supply (from the USB port), many data acquisition units have a complex input circuit containing a voltage divider and a bias voltage source. An ad-hoc correction technique of error due to input resistance of data acquisition (DAQ) units without reference and high-precision equipment is proposed. The technique does not require complex hardware and software. The results of modelling show that with a confidence probability of 0.9973, the deviations of electromotive force and resistance do not exceed 0.9% and 5.6%, respectively