Op-Amp Gain Calculator

Inverting Configuration

V

Results

Gain (Av):

-10

Output Voltage (Vout):

-10 V

Formula:

Av = -Rf/Rin

Vout = Av × Vin

Circuit Diagram

Non-Inverting Configuration

V

Results

Gain (Av):

11

Output Voltage (Vout):

11 V

Formula:

Av = 1 + (Rf/R1)

Vout = Av × Vin

Circuit Diagram

Voltage Calculator

V
V

Results

Gain (Av):

10

Input Voltage (Vin):

1 V

Output Voltage (Vout):

10 V

Formula:

Vout = Av × Vin

Av = Vout / Vin

Vin = Vout / Av

Bandwidth Estimation

Hz
Typically 1MHz for common op-amps like 741

Results

Bandwidth:

100 kHz

Gain-Bandwidth Product:

1 MHz

Formula:

Bandwidth = GBP / Av

Where GBP is the Gain-Bandwidth Product

Information

The gain-bandwidth product (GBP) is a key parameter of operational amplifiers that remains constant for a given op-amp. As you increase the closed-loop gain, the bandwidth decreases proportionally.

Common GBP values:

  • LM741: 1 MHz
  • TL081: 3 MHz
  • OP27: 8 MHz
  • LM318: 15 MHz

Reverse Calculation

This will be Rin for inverting or R1 for non-inverting

Results

Input Resistor (Rin):

1 kΩ

Feedback Resistor (Rf):

10 kΩ

Actual Gain:

10

Formulas:

For inverting: Rf = |Av| × Rin

For non-inverting: Rf = (Av - 1) × R1

Op-Amp Gain Guide

Inverting Amplifier

An inverting amplifier produces an output that is the inverted and amplified version of the input signal. The gain is determined by the ratio of the feedback resistor (Rf) to the input resistor (Rin).

Key characteristics:

  • Gain: Av = -Rf/Rin
  • Input impedance is approximately Rin
  • Output is inverted (180° phase shift)
Non-Inverting Amplifier

A non-inverting amplifier produces an output that is in phase with the input signal. The gain is always greater than or equal to 1.

Key characteristics:

  • Gain: Av = 1 + (Rf/R1)
  • High input impedance (theoretically infinite)
  • Output is in phase with input
Practical Considerations

Resistor Selection: Choose resistor values in the range of 1kΩ to 100kΩ for best results. Very low values may overload the op-amp, while very high values may increase noise.

Bandwidth: All op-amps have a finite bandwidth. The gain-bandwidth product (GBP) determines how much gain you can achieve at a given frequency.

Power Supply: Ensure your power supply voltages are sufficient for the desired output swing. Most op-amps can't output voltages equal to their supply rails.

Example Calculations
Inverting Example

Given:

  • Rin = 1kΩ
  • Rf = 10kΩ
  • Vin = 0.5V

Gain = -10kΩ/1kΩ = -10

Vout = -10 × 0.5V = -5V

Non-Inverting Example

Given:

  • R1 = 1kΩ
  • Rf = 9kΩ
  • Vin = 0.5V

Gain = 1 + (9kΩ/1kΩ) = 10

Vout = 10 × 0.5V = 5V