- Construct the circuit shown in Fig. 1 and measure the impedance across EACH side, face, and diagonal of the resistive cube (Hint: there should be 28 measurements total).
- Take out each individual resistor from the cube and measure its resistance value separately.
- Construct the circuit shown in Fig. 2 with two R-2R stages and measure the input impedance. Repeat the measurement for circuits with 1 - 7 stages and measure the input impedance of each. Let R = 1 k Ohm.
- Measure the value of each resistor in the ladder separately and record its location in the 9-stage ladder network.
- Construct the circuit shown in Fig. 3 for the 3-stage D/A converter. Let R = 1 k Ohm. Measure the open circuit voltage and the short circuit current when the input is "4" and the voltage source is 5 volts. Repeat the voltage and current measurements for inputs of "1" and "2". Measure the input impedance.
- Construct the circuit shown in Fig. 4 and measure the output voltage (magnitude and phase) from 1 Hz to 100 kHz. Normalize the result to the input signal. Use the "waveform math" menu to display the input (channel 1) vs the output (channel 4). Print the result.
- Extra Credit (10%) Construct the circuit shown in Fig. 5 and find the frequency where the output voltage is a maximum. Find the equivalent non-ideal voltage source at this frequency. Measure the output voltage magnitude at frequencies up to 100 times higher and lower than the optimal frequency.
Post-lab analysis:
Generate a lab report following the sample report available on the Web page. Mention any difficulties encountered during the lab. Describe any results that were unexpected and try to account for the origin of these results (i.e. explain what happened). IN ADDITION, respond to the following questions/instructions:- What is the average value and standard deviation of the resistances in the cube (a) according to the cube measurements and (b) according to the direct measurements of the resistances?
- Plot the value of the input impedance of the R-2R ladder as a function of the number of stages. Estimate the asymptotic value of the ladder as the number of stages gets very large. Compare the results with the calculations (plot on the same curve) and compute the average value and standard deviation of the ladder resistors.
- Use the measurements to compute the Thevenin equivalent non-ideal voltage source for all three input cases.
- Use the measurements to compute the Thevenin equivalent source if the input were "6" (show your work). Compare this to the value that you calculated.
- Plot the results of the measurements with the circuit in Fig. 4 and compare the results to the simulations. Explain any discrepancies that you find.
- Interpret the plot containing the "waveform math".
- If you did the extra credit, compare the simulations with the experimental results for the circuit in Fig. 5.
