Inverting Op Amp Formula

Inverting Amplifier Formula:

\[ Gain = -\frac{R_f}{R_{in}} \]

Gain:

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Inverting Op Amp Formula?

The inverting operational amplifier configuration is one of the most fundamental and widely used op-amp circuits. It produces an output signal that is 180 degrees out of phase with the input signal, with the gain determined by the ratio of feedback resistance to input resistance.

2. How Does the Calculator Work?

The calculator uses the inverting amplifier formula:

\[ Gain = -\frac{R_f}{R_{in}} \]

Where:

\( R_f \) — Feedback resistance (ohms)
\( R_in \) — Input resistance (ohms)
\( Gain \) — Voltage gain (unitless)

Explanation: The negative sign indicates phase inversion, and the gain magnitude is determined by the ratio of the two resistors. The formula assumes an ideal op-amp with infinite input impedance and zero output impedance.

3. Importance of Gain Calculation

Details: Accurate gain calculation is essential for designing amplification circuits, signal processing systems, and various electronic applications where precise voltage amplification with phase inversion is required.

4. Using the Calculator

Tips: Enter feedback resistance and input resistance in ohms. Both values must be positive and non-zero. The calculator will compute the voltage gain, which is a unitless quantity representing the amplification factor.

5. Frequently Asked Questions (FAQ)

Q1: Why is the gain negative in the formula?
A: The negative sign indicates that the output signal is inverted (180 degrees out of phase) relative to the input signal, which is characteristic of inverting amplifier configurations.

Q2: What are typical resistance values used in practice?
A: Typical values range from 1kΩ to 1MΩ. The specific values depend on the application requirements, available components, and desired input/output impedance characteristics.

Q3: What are the limitations of this ideal formula?
A: The ideal formula assumes infinite open-loop gain, infinite input impedance, and zero output impedance. Real op-amps have limitations that may affect performance at high frequencies or with very large gain values.

Q4: Can this configuration be used for AC signals?
A: Yes, the inverting amplifier works for both DC and AC signals. For AC signals, the gain applies to the amplitude while maintaining the 180-degree phase shift.

Q5: How does this compare to non-inverting amplifier configuration?
A: The non-inverting configuration provides positive gain without phase inversion and has higher input impedance, but the inverting configuration offers better stability and is easier to implement for certain applications.