Difference Amplifier (Week 6 - Day 12)

     In the previous experiment, we were to use an operational amplifier in order to sum voltages. In this segment, we tested the versatility of an op-amp by finding the difference between input voltages.

A schematic of the circuit was created on EveryCircuit.

We chose all our resistors to have same values

The equation that describes the output voltage is given by v_b - v_a.

Below is an image of the circuit we constructed from our schematic.

R₁ =R₂ = R₃ = R₄ = 10kΩ 

Their measured values were 9.91kΩ, 9.90kΩ, 9.92kΩ, and 9.89kΩ, respectively.

In the first part of this experiment, we kept v _{at a constant 1V, and the returned values were:}

Graph of V_b = 1V (Vout v. Vin)

Graph of V_b = -1V (Vout v. Vin)

     This experiment was a success as the one before. We were not surprised by the values we measured, except for some, but they were due to the same error as our previous lab. We reached saturation at voltages above ~3.5V and below ~-3.5V. It was an overall success with minimal percent error.