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Op-Amp Gain Calculator

Calculate inverting and non-inverting op-amp gain from the feedback and input resistors, in V/V and dB, plus the output voltage.

R_in is the resistor from the source to the amplifier input; R_f is the feedback resistor from output to the inverting input.
Inverting gain (−R_f/R_in)–
Non-inverting gain (1 + R_f/R_in)–
Gain magnitude in dB–
Output (inverting)–
Output (non-inverting)–
InvertingV_inR_inR_f−+V_outNon-invertingV_in+−V_outR_fR_in
Same two resistors, different input — that's the whole difference

Op-amp gain

With negative feedback, an ideal op-amp's closed-loop gain is set only by the two resistors — not the op-amp itself. The two classic configurations give different gains and input behaviour.

Inverting: A_v = −R_f / R_in

Non-inverting: A_v = 1 + R_f / R_in

The inverting amp flips the signal's polarity (hence the minus sign) and its gain can be below 1; the non-inverting amp keeps polarity and its gain is always at least 1. Gain in decibels is 20·log₁₀|A_v|.

Related

Set the resistor values with theresistor series & parallelcalculator, or convert a dB figure with thedecibel converter.

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