# 10.5: Procedure

## 10.5.1: Circuit 1

1. Using Figure 10.4.1 with a 10 kHz sine wave at 10 V p-p source, R = 1 k$$\Omega$$, L = 10 mH, and C = 10 nF, determine the theoretical inductive and capacitive reactances, parallel branch reactance and total circuit impedance, and record the results in Table 10.6.1 (the experimental portion of this table will be filled out in step 5). Using Ohm’s law and the voltage divider rule compute the capacitor and inductor-resistor voltages along with the input current and record them in Table 10.6.2.

2. Build the circuit of Figure 10.4.1 using R = 1 k$$\Omega$$, L = 10 mH, and C = 10 nF. Set the generator to a 10 kHz sine wave and 10 V p-p. Make sure that the Bandwidth Limit of the oscilloscope is engaged for both channels. This will reduce the signal noise and make for more accurate readings.

3. Place probe one across the generator and probe two across the parallel inductor-resistor branch. Using the Math function, the capacitor voltage may be found by subtracting the voltage of probe two from that of probe one. Also, the input current may be found by dividing the capacitor’s voltage by its reactance. Measure the parallel branch voltage and capacitor voltage, both magnitude and phase, and record in Table 10.6.2. Compute the input current and record in Table 10.6.2.

4. Take a picture of the three voltage waveforms.

5. Compute the deviations between the theoretical and experimental values of Table 10.6.2 and record the results in the final columns of Table 10.6.2. Based on the experimental values, determine the experimental total Z and parallel branch Z values via Ohm’s law (e.g., $$Z_T = V_{in}/i_{in}$$) and record back in Table 10.6.1 along with the deviations.

6. Create a phasor plot showing $$V_{in}$$, $$V_{LR}$$, and $$V_C$$. Include both the time domain display from step 4 and the phasor plot with the technical report.

## 10.5.2: Circuit 2

7. Using Figure 10.4.2 with a 10k Hz sine wave at 10 V p-p, R = 1 k$$\Omega$$, L = 10 mH, and C = 10 nF, determine the theoretical inductive and capacitive reactances, series branch impedance and total circuit impedance, and record the results in Table 10.6.3. Using Ohm’s law compute the capacitor and inductor-resistor currents along with the input current and record them in Table 10.6.4.

8. Build the circuit of Figure 10.4.2 using R = 1 k$$\Omega$$, L = 10 mH, and C = 10 nF. Insert a 10 $$\Omega$$ current sense resistor at the bottom of the LR leg and another at the bottom of the capacitor leg. Set the generator to a 10 kHz sine wave and 10 V p-p. Make sure that the Bandwidth Limit of the oscilloscope is engaged for both channels. This will reduce the signal noise and make for more accurate readings.

9. Place probe one across the generator and probe two across the inductor-resistor branch sense resistor. The inductor-resistor current may be found by dividing the probe two voltage by the sense resistor. The capacitor current is found in a similar manner using its current sense resistor (use probe three if available, otherwise perform this twice using probe two). Record both magnitude and phase of the two currents in Table 10.6.4.

10. Take a picture of the $$V_{in}$$ and $$i_{LR}$$ sense waveforms and also of the $$V_{in}$$ and $$i_C$$ sense waveforms (one combined picture if using three probes, otherwise two separate pictures).

11. To measure the input current, remove the two sense resistors and place one of them so that it is between ground and the bottom junction of the resistor and capacitor. Move probe two to this sense resistor and measure the voltage. From this, compute the total current and record both magnitude and phase in Table 10.6.4.

12. Take a picture of the $$V_{in}$$ and $$i_{in}$$ sense waveforms.

13. Compute the deviations between the theoretical and experimental values of Table 10.6.4 and record the results in the final columns of Table 10.6.4. Based on the experimental values, determine the experimental total Z and series branch Z values and record back in Table 10.6.3 along with the deviations.

14. Create a phasor plot showing $$i_{in}$$, $$i_{LR}$$, and $$i_C$$. Include both the time domain displays from steps 10 & 12 and the phasor plot with the technical report.

## 10.5.3: Computer Simulation

15. Build the circuit of Figure 10.4.1 in a simulator. Using Transient Analysis, determine the voltage across the inductor and compare the magnitude and phase to the theoretical and measured values recorded in Table 10.6.2.