Networks I - Lab Section 6: Mondays 12.15-3.00 pm

Lab Assignment 5 -       due: next Monday, 16 October 2006

Lab 5 – The Op-Amp

Objectives: The objective of this lab is to become familiar with the use of an Op-Amp to perform a signal processing operation.  An Op-Amp can be used as both an inverting amplifier and a non-inverting amplifier.

Part 1:

Based on the Op-Amp fundamentals learned in class, solve for the output of the inverting amplifier in Figure 1.  First, write the ideal Op-Amp equations.  Next, evaluate KCL at node A and solve for Vout/Vin (which is a calculation of the gain of the amplifier) leaving the resistors as variables.

Figure 1 - Inverting Op-Amp

Build the circuit in Figure 1 using either an LMC662 (National Semiconductor) or an MC4741C (Motorola) IC and measure all voltages and currents and the gain of the circuit.  Using the resistors values from your circuit evaluate the voltages, currents and gain analytically.  Compare the experimental results with the calculated voltages and currents throughout the circuit.  Explain any differences.  Next, change both of the resistor values and compare the gains with your calculations.  Comment on your results.

Part 2:

Based on the Op-Amp fundamentals learned in class, solve for the output of the non-inverting amplifier in Figure 2.  Using the same steps in part 1, calculate all the electrical parameters.

Figure 2 - Non-Inverting Op-Amp

Build the circuit in Figure 2 again using either an LMC662 (National Semiconductor) or an MC4741C (Motorola) IC and measure all voltages and currents and the gain of the circuit.  Using the resistors values from your circuit evaluate the voltages, currents and gain analytically.  Compare the experimental results with the calculated voltages and currents throughout the circuit.  Explain any differences.  Next, change both of the resistor values and compare the gains.  Comment on your results.

Part 3:

Finally, build all four (4) different Op-Amp circuits you created above in Mentorgraphics, solve for the gains of all your non-inverting and inverting amplifiers

Part 4: (Extra-Credit)

Build an electronic circuit using different Op-Amps to create the linear algebra equation below and develop a simulation of it in Mentorgraphics: (see text pages 209-213 for assistance)

Z = 3x - 4y + 2  where output voltage Z depends upon two other variable voltage sources x and y