13.5: Procedure

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1. For the circuit of Figure 13.4.1, calculate the voltage across the 1 k\(\Omega\) load using R1 = 1.5 k\(\Omega\), R2 = 2.2 k\(\Omega\), and C = 470 nF, with a 2 V p-p 1 kHz source. Record this value in Table 13.6.1. Also calculate the expected Thevenin voltage and Thevenin impedance. Record these values in Table 13.6.2.

2. Build the circuit of Figure 13.4.1 using R1 = 1.5 k\(\Omega\), R2 = 2.2 k\(\Omega\), Rload = 1 k\(\Omega\) and C = 470 nF. Set the generator to a 1 kHz sine wave at 2 V p-p. Make sure that the Bandwidth Limit of the oscilloscope is engaged. This will reduce the signal noise and make for more accurate readings. Measure the load voltage and record in Table 13.6.1 as \(V_{Load}\) Original.

3. Remove the load and measure the unloaded output voltage. This is the experimental Thevenin voltage. Record it in Table 13.6.2.

4. Replace the voltage source with a 50 \(\Omega\) resistor to represent its internal impedance. Set the impedance meter to 1 kHz and measure the resulting impedance at the open load terminals. This is the experimental Thevenin impedance. Record these values in Table 13.6.2 and compare with the theoretical values.

5. Using the decade resistance box and capacitor, build the Thevenin equivalent circuit of Figure 13.4.2 and apply the 1 k\(\Omega\) load resistor. Measure the load voltage and record in Table 13.6.1. Compare with the values of the original (non-Thevenized) circuit and determine the deviation between the original and Thevenized circuits.

6. To verify that Thevenin’s Theorem also works with an inductive source and a complex load, repeat steps 1 through 5 in like manner but using Figure 13.4.3 with R1 = 1.5 k\(\Omega\), R2 = 2.2 k\(\Omega\), L = 10 mH, Rload = 1 k\(\Omega\) with Cload = 100 nF. Set the generator to a 10 kHz sine wave at 2 V p-p. Record results in Tables 13.6.3 and 13.6.4.