5CH - Differential mode op amp

More on differential op amps today. Proved the equation through experiment last week so moved on to work through some examples. Remember that Rf/R1 must equal R3/R2 for this equation to hold.

When you are identifying a differential mode amplifier, remember that it has two input resistors. Meaning that it has two input voltages. All the amplifier does is amplify this difference in voltage (make sure you know which is V2 and which is V1 as this might not always be given).