<^< Inverting Amplifier | Course Index | Non-inverting Amplifier >^>
| Objective:
| To investigate an inverting operational amplifier.
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| Underpinning knowledge:
| Operational amplifier symbols and connections.
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| Apparatus:
| TINA circuit file, or apparatus to make the following circuit.
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| TINA Circuit File:
| Click here to download circuit file
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| Initial Settings:
| Vin = +1V, RIN = RF = R1 = 100kΩ.
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| Requires:
| Paper, Linear graph paper, pen or pencil.
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| Instructions:
(a) Set Vin = +1V
(b) Set RIN = RF = R1 = 100kΩ
(c) Measure and record the values of Vin and Vout (using VM1).
(d) Repeat (c) for each of the following conditions:
- RF = 200kΩ
- RF = 400kΩ
- RF = 600kΩ
- RF = 800kΩ
- RF = 1MΩ
(e) Set Vin = -1V
(f) Repeat steps (b) to (d) above.
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Observations:
(a) Comment on the results obtained.
(b) Show that the output voltage, Vout, of the amplifier is given by: Vout = AV x Vin and AV is the voltage gain of the amplifier given by: AV = -RF/RIN
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| Further work:
With RF set to 1MΩ, vary the input voltage, Vin, from -1V to +1V in appropriate steps and record values of Vout. Use these values to plot a graph showing the relationship between Vout and Vin. What does the slope of this graph indicate?
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<^< Inverting Amplifier | Course index | Non-inverting Amplifier >^>
