TABLE OF CONTENTS In the case of a differential amplifier, the input signals are applied to both the inverting input terminal and the noninverting input terminal.
The configuration can be drawn as shown in Figure 4.7.
Here also, the ideal op-amp characteristics are assumed.
The voltage at node ' A', should be equal to voltage at node ' B.'
| (4.25) |  |
Writing Kirchhoff's Current Law at node ' A' yields
or
| (4.26) |  |
Writing Kirchhoff's Current Law at node ' B' yields
Substitute equation (4.25) here:
or
| (4.27) |  |
Substitute equation (4.27) in equation (4.26),
It is standard practice to take R 1 = R 2 and R 3 = R f
| (4.28) |  |
Therefore, output is the amplified version of the difference between the two input terminals.
