The input impedance of this module is very high, if U1 is OP07 it is in mega ohms, use CA3140 or LF356 fet input opamps to get 1 tera ohm input impedance, but for high gains OP07 is better as it is ultra low offset, this is a good amplifier for sensor outputs, as in a DC Circuit.
Non-Inverting Opamp Interactive Simulation
This High-Input Impedance configuration is commonly used in front end of sensor signal conditioner and Meters. This page Includes an Interactive Tutorial with Simulated Meters and Potentiometers, demonstrating how a Non-Inverting Operational Amplifier functions.
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