Logarithmic current electrometer using commercially available Current conveyor AD844

摘要

Logarithmic current measurements have been made with log ratio amplifier using commercially available current conveyor AD844. The proposed circuit is designed to measure currents from 1 mu A to 0.1 mA. Temperature compensation is achieved using the thermistor technique in the temperature range 25-70 degrees C. Variations in the scale factor as a function of the input current is also discussed.