Formula
This calculator uses the standard op-amp gain calculator formula:
Frequently Asked Questions
Op-amp gain is the ratio of output voltage to input voltage. For an ideal non-inverting amplifier: Gain = 1 + Rf/R1. For inverting: Gain = −Rf/R1.
An inverting amplifier flips the phase of the output signal. A non-inverting amplifier maintains the same phase. Both amplify the signal; the choice depends on phase requirements.
For non-inverting: 1 + Rf/R1 = 10, so Rf/R1 = 9. Use Rf = 90 kΩ and R1 = 10 kΩ. For inverting: −Rf/R1 = −10, so Rf = 100 kΩ and R1 = 10 kΩ.
Decibel gain = 20 × log₁₀(|Av|). A gain of 10 = 20 dB; gain of 100 = 40 dB; gain of 0.1 = −20 dB (attenuation).
The gain-bandwidth product (GBW) is a fixed value for a given op-amp. As gain increases, bandwidth decreases proportionally. For example, GBW=1 MHz at gain=10 gives 100 kHz bandwidth.
A voltage follower is a non-inverting op-amp with Rf = 0 and R1 = infinity (or just the output connected to the inverting input), giving Gain = 1. It provides high input impedance and low output impedance.