±100V input differential amplifier with great efforts in parameter selection

In the standard adjustable amplifier circuit, when the gain is constant, Ri and I have
a certain ratio. In this circuit, by selecting R:=RI/l0 and R=RI/10, the positive input terminal of the OP amplifier is 1llOa:' of
the common input voltage . The stiffness
attenuates the voltage across R5 and R. In the voltage dividing circuit formed, take R, = R6 (A -1)
, so that
    the resistance value of the voltage dividing circuit with an amplification factor of 10 is not much lower than U. , an error will occur.
When selecting , a buffer amplifier should be added to the output end of the voltage divider circuit . The resistance ratio of this circuit is about
1000, so the error is within 0-1%. If you use
a resistor with a fixed error of ±1", it is of little significance.
    Although the amplification of this circuit is l, the internal voltage amplification is 10 times,
so the loop gain is reduced by 20dB, and the offset drift is also expanded by 10. For this reason, either the differential voltage
signal should be increased as much as possible during design , or a precision OP amplifier should be used .