Higher Physics

Electricity and Electronics - Activity 20

The differential amplifier

Aim - To investigate the Op-Amp operating in the differential mode     Instructions

 
  • For each of the values of R1 and R2, V2 and V1 given in the table below, record the output voltage V0.
  • Copy the table and complete the other columns.
  • Comment on the polarity of  V0 compared to ( V2 - V1 )
Copyright Physics Support Materials 2000
Rf &R3
(W)		 R1 &R2
(W)		 Rf /R1 V2
(V)		 V1
(V)		 V2-V1
(V)

V0
(V)

Rf /R1(V2-V1)
(V)

100 k 100 k   6.0 2.0      
100 k 100 k   1.0 4.0      
100 k 100 k   5.0 -2.5      
100 k 100 k   -1.5 -3.0      
100 k 10 k   3.5 3.0      
100 k 10 k   1.5 2.5      
100 k 10 k   -4.5 -5.0      
100 k 10 k   -1.5 -2.0