A basic differential amplifier using only one OP amplifier

The figure shows a resistive bridge circuit driven by a unipolar current . We
use this as an example to illustrate the operation of the differential amplifier circuit. When balanced input, el and e▲ are equal
, each is E/20. ez is divided by Rz and Zhan' and then added to the non-inverting input port.
    Because when the OP amplifier works in the linear range, the box phase input terminal and the non-
inverting input terminal have the same potential . , so e. _厯 Chou, the output voltage eo after dividing by Ra and Ra should
be equal to zero.