Enter your resistor values R1, R2, R3, and R4 (in Ohms) along with V1 (Inverting Input) and V2 (Non-Inverting Input) into this Differential Amplifier Calculator to find the Output Voltage, Differential Gain, and the voltages at both the V+ (Non-Inverting Terminal) and V- (Inverting Terminal).
Output Voltage
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Differential Gain
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V+ (Non-Inverting Terminal)
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V- (Inverting Terminal)
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A differential amplifier is an electronic circuit that amplifies the difference between two input voltages while rejecting signals common to both inputs. It's commonly built using operational amplifiers with four external resistors.
The differential gain is calculated as (R2/R1) when the circuit is balanced (R4/R3 = R2/R1). For unbalanced circuits, the gain depends on both the differential input and common-mode rejection.
Unmatched resistor ratios will result in poor common-mode rejection, meaning the amplifier will amplify common signals present on both inputs instead of rejecting them. This reduces the circuit's performance.
The calculations assume an ideal op-amp with infinite input impedance, zero output impedance, infinite open-loop gain, and that the inverting and non-inverting inputs are at the same voltage (virtual short).
No, the actual output voltage is limited by the op-amp's supply voltages. If the calculated output exceeds these limits, the op-amp will saturate and clip the output signal.
Choose R1 and R3 to set the input impedance (typically 10kΩ-100kΩ). Then select R2 and R4 to achieve the desired gain while maintaining the ratio R4/R3 = R2/R1 for good common-mode rejection.
In a pure inverting configuration, set V2 to 0V and use V1 as input. For non-inverting, set V1 to 0V and use V2. The differential amplifier responds to the difference V2-V1.