Operational amplifiers are widely used in electronic circuits for signal amplification. Calculating the gain of these circuits is essential for designing and analyzing their performance. This guide provides a clear, step-by-step process to determine the gain in various operational amplifier configurations.

Understanding Operational Amplifier Basics

An operational amplifier (op-amp) is a high-gain voltage amplifier with differential inputs. The gain of an op-amp circuit depends on the external resistors connected around it. Common configurations include inverting, non-inverting, and differential setups.

Calculating Gain in Inverting Amplifier Circuits

In an inverting amplifier, the input signal is applied to the inverting input through a resistor, and a feedback resistor connects the output to the inverting input. The non-inverting input is grounded.

The voltage gain (Av) is calculated using the formula:

Av = - Rf / Rin

Where Rf is the feedback resistor and Rin is the input resistor.

Calculating Gain in Non-Inverting Amplifier Circuits

In a non-inverting amplifier, the input signal is applied to the non-inverting input. The feedback resistor connects the output to the inverting input, which is also connected to ground through another resistor.

The voltage gain is given by:

Av = 1 + (Rf / Rin)

Summary of Gain Formulas

  • Inverting amplifier: Av = - Rf / Rin
  • Non-inverting amplifier: Av = 1 + (Rf / Rin)