Inverting Amplifier Calculator

An inverting amplifier is an op-amp circuit that boosts an input signal while flipping its polarity — a 2V input becomes a larger negative voltage at the output. Enter your Input Voltage (Vin), Input Resistor (R1), Feedback Resistor (R2), and supply voltages (Vcc/Vee) into the Inverting Amplifier Calculator to find the Output Voltage (Vout). Secondary outputs include Amplifier Gain (Av), Gain in dB, and Input Current.

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Input signal voltage applied to the inverting terminal

kΩ

Resistor between input voltage and inverting terminal

kΩ

Feedback resistor from output to inverting terminal

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Positive supply voltage to op-amp

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Negative supply voltage to op-amp

Results

Output Voltage (Vout)

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Amplifier Gain (Av)

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Gain in dB

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Input Current

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Frequently Asked Questions

What is an inverting amplifier?

An inverting amplifier is an operational amplifier configuration where the input signal is applied to the inverting (-) terminal, and the output is 180 degrees out of phase with the input. The gain is determined by the ratio of feedback resistor to input resistor.

How do you calculate the gain of an inverting amplifier?

The voltage gain of an inverting amplifier is calculated using the formula: Av = -R2/R1, where R2 is the feedback resistor and R1 is the input resistor. The negative sign indicates phase inversion.

What happens if the output voltage exceeds the supply voltage?

If the calculated output voltage exceeds the supply voltage limits (Vee to Vcc), the op-amp will saturate and clip the output at the supply rail voltages. This causes distortion in the output signal.

Why is the output voltage negative for positive input in an inverting amplifier?

The inverting amplifier inverts the phase of the input signal by 180 degrees. This means a positive input voltage produces a negative output voltage, and vice versa, due to the feedback configuration.

What is the typical input impedance of an inverting amplifier?

The input impedance of an inverting amplifier is approximately equal to the input resistor R1, which is much lower than the input impedance of a non-inverting amplifier configuration.

How do you choose resistor values for an inverting amplifier?

Choose resistor values based on desired gain (R2/R1 ratio), input impedance requirements, and power considerations. Typical values range from 1kΩ to 1MΩ, with higher values reducing power consumption but increasing noise susceptibility.

Can an inverting amplifier have a gain less than 1?

Yes, an inverting amplifier can have a gain less than 1 (attenuation) when the feedback resistor R2 is smaller than the input resistor R1. This creates an inverting attenuator circuit.

What is the bandwidth of an inverting amplifier?

The bandwidth of an inverting amplifier depends on the op-amp's gain-bandwidth product and the closed-loop gain. Higher gains result in lower bandwidth due to the gain-bandwidth trade-off in op-amp circuits.