Recent Changes - Search:

Electronic circuits and components

Fundamentals

Passive Components

Semiconductors

Passive Circuits

Active Circuits

Parts Gallery

Worksheets: Differential Amplifier

<^< Differential Amplifier | Course Index | Direct Coupled Amplifier >^>

Objective: To investigate a differential operational amplifier.
Underpinning knowledge: Operational amplifier symbols and connections.
Apparatus: TINA circuit file, or apparatus to make the following circuit.
TINA Circuit File: Click here to download circuit file
Initial Settings: Vin1 = Vin2 = 0V, R1 = R2 = 100kΩ, R3 = R4 = 500kΩ
Requires: Paper, Linear graph paper, pen or pencil.
Instructions:

(a) Set R1 = R2 = 100kΩ and R3 = R4 = 500kΩ

(b) Set Vin1 and Vin2 to 0V

(c) Measure and record the values of Vin1, Vin2 and Vout (using VM1).

(d) Repeat (c) for each of the following conditions:

  • Vin1 = +1V and Vin2 = 0V
  • Vin1 = 0V and Vin2 = +1V
  • Vin1 = -1V and Vin2 = 0V
  • Vin1 = 0V and Vin2 = -1V
  • Vin1 = +1V and Vin2 = +1V
  • Vin1 = -1V and Vin2 = -1V

(e) Set R1 = R2 = 100kΩ and R3 = R4 = 1MΩ

(f) Repeat (b) to (d) above.

Observations:

(a) Comment on the results obtained.

(b) Show that the output voltage, Vout, of the amplifier is given by: Vout = -RF/Rin x (Vin1 - Vin2) where RF = R3 = R4 and Rin = R1 = R2

Further work:

With R3 = R4 = 1MΩ and R1 = R2 = 100kΩ, use the data obtained earlier to plot a graph showing the relationship between Vout and (Vin1 - Vin2). What does the slope of this graph indicate?

<^< Differential Amplifier | Course index | Direct Coupled Amplifier >^>

Print - Search - Login

Page last modified on July 28, 2011, at 09:55 AM