What must be checked before using the Inverting amplifier relation?

Confirm negative feedback, the virtual node and that Vo does not saturate.

13. Amplifiers and op-amps

Inverting amplifier

Formula

v_o=-\frac{R_f}{R_{\mathrm{in}}}v_{\mathrm{in}}

Detail

The inverting amp uses the virtual short: Vo=−(Rf/Rin) Vin with v+≈v− at ground.

Explore the idea

Variables

$v_+,v_-,v_o,v_{\mathrm{in}}$ V
$A$ gain (dimensionless)
$R_f,R_{\mathrm{in}},R_g$ Ω
$\mathrm{CMRR}$ dimensionless.

Conditions

Ideal op-amp with negative feedback except comparator; |Vo| < Vsat.

Intuitive explanation

For “Inverting amplifier”: with negative feedback v+ ≈ v− (virtual node) and the resistor network sets the gain.

Worked example

With

R_{\mathrm{in}}=10\,\mathrm{k\Omega}

R_f=100\,\mathrm{k\Omega}

and

v_i=0.2\,\mathrm V

v_o=-2.0\,\mathrm V

Common mistakes

forgetting the virtual node
using inverting gain on a non-inverter
ignoring |Vo| < Vsat

Frequently asked questions

What must be checked before using the Inverting amplifier relation?: Confirm negative feedback, the virtual node and that Vo does not saturate.

Also known as

inverting amplifier
inverting op amp

Conventions

V or dimensionless

Last reviewed: 2026-09-19

Found an error? Contact us.

Related formulas

13. Amplifiers and op-amps

Inverting amplifier

In 13. Amplifiers and op-amps

Formula

v_o=-\frac{R_f}{R_{\mathrm{in}}}v_{\mathrm{in}}

Detail

The inverting amp uses the virtual short: Vo=−(Rf/Rin) Vin with v+≈v− at ground.

Explore the idea

Variables

$v_+,v_-,v_o,v_{\mathrm{in}}$ V
$A$ gain (dimensionless)
$R_f,R_{\mathrm{in}},R_g$ Ω
$\mathrm{CMRR}$ dimensionless.

Conditions

Ideal op-amp with negative feedback except comparator; |Vo| < Vsat.

Intuitive explanation

For “Inverting amplifier”: with negative feedback v+ ≈ v− (virtual node) and the resistor network sets the gain.

Worked example

With

R_{\mathrm{in}}=10\,\mathrm{k\Omega}

R_f=100\,\mathrm{k\Omega}

and

v_i=0.2\,\mathrm V

v_o=-2.0\,\mathrm V

Common mistakes

forgetting the virtual node
using inverting gain on a non-inverter
ignoring |Vo| < Vsat

Frequently asked questions

What must be checked before using the Inverting amplifier relation?: Confirm negative feedback, the virtual node and that Vo does not saturate.

Also known as

inverting amplifier
inverting op amp

Conventions

V or dimensionless

Last reviewed: 2026-09-19

Found an error? Contact us.

Inverting amplifier

Tags

Detail

Explore the idea

Variables

Conditions

Intuitive explanation

Worked example

Common mistakes

Frequently asked questions

Also known as

Related topics

Conventions

Related formulas

Inverting amplifier

Tags

Detail

Explore the idea

Variables

Conditions

Intuitive explanation

Worked example

Common mistakes

Frequently asked questions

Also known as

Related topics

Conventions

Related formulas