Differential Amplifier (Subtractor)

Working principle

A differential op-amp amplifies the difference between two input voltages (V_in1 and V_in2).

Formula derivation

If Vin2 = 0, 

If Vin1 = 0, 

Given that:

Experiments

• Equate R₁ to R₃, and R₂ to R₄ to transform this circuit into a voltage subtractor with the output (R₂/R₁)*(V_in2-V_in1).
• Equate all resistor values. What is the output in terms of the input voltages now?