Experimental study of fA level micro-current measurement

It´s difficult but of great research significance to detect the fA level micro-current with the operational amplifier. This article analyzed the non-ideality parameters of the operational amplifier in the current to voltage converter circuit, and attempted to detect the fA level micro-current by compensating the detecting errors directly. Finally, the experiments proved that the strictly chosen operational amplifiers with low bias current, low offset voltage and low temperature drift still maintain good linear characteristics in fA level micro-current detection. The result indicated that it is really possible to detect the current which is far smaller than the input bias current with the operational amplifier.