AC Parallel RLC Circuit

Figure 1: Parallel R, C, L Circuit

Frequency Hz	L & C Admittances in Rectangular Form
	Inductor GL - jBL	Capacitor GC + jBC
550
1000

Frequency Hz	Total Circuit Admittance YT
	Rectangular Form GT + jBT	Magnitude	Angle
550
1000

Frequency Hz	Total Circuit Impedance ZT
	Rectangular Form RT + jXT	Magnitude	Angle
550
1000

Table 1 – Calculated RLC Admittance and Impedance Values

2. Calculate and record the following quantities:

Frequency Hz	IR (RMS). A	IC (RMS), A	IL (RMS). A
	Magnitude	Angle	Magnitude	Angle	Magnitude	Angle
550
1000

Frequency Hz	{IR + IC + IL }= IS (RMS), A	IS = V * YT
	Rectangular Form	Magnitude	Angle	Magnitude	Angle
550
1000

Table 2 – Calculated RLC Component Current Values

Does the sum of the magnitudes of the three currents IR, IC, and IL, in the table above, equal the current, IS, calculated directly in the last column?

(YES or NO)

Explain why your answer is what it is.

3. Calculate the power dissipated by the parallel resistor and the power supplied by the source:

Frequency Hz	PR, W	PS, W
550
1000

Table 3 – Calculated RLC Resistor Power Dissipation

B. Multisim Simulation and Circuit Calculations

1. Launch MultiSim and build the circuit schematic shown in Figure 2. Include the AC Power source and the DMMs.

2. Set both DMMs, XMM1 thru’ XMM4, to read AC measurements and Current, I. See fig. 2 below.

Figure 2: MultiSim RLC Parallel Circuit with Instrumentation

3. Activate the simulation and record the current readings for both frequencies:

Frequency Hz	IS (RMS), A	IR (RMS), A	IC (RMS), A	IL (RMS), A
550
1000

Table 4 – Current Measurements Simulation Results

4. Do the current values in Table 4 agree with those obtained in Tables, 2, 3, & 4 of Part A? (Circle your answer)

YES NO

5. Remove the DMMs and attach the wattmeter as shown below:

Figure 3 - AC Power Measurement

6. Record the measurement from the wattmeter.

Frequency Hz	Source Power, PS (Watts)	Power Factor
550
1000

Table 5 - Power Measurement Readings

7. Do values in the Tables 6 and 2 agree? (Circle your answer)

YES NO

If there is any disagreement investigate the source of error and report your findings below:

C. Construction of a Parallel R, L, C Circuit and Measurement of Circuit Characteristics

1. Construct the circuit in Figure 1.

2. Set the function generator voltage to 2.5 V RMS and the frequency value to 550 Hz.

3. Turn the circuit on.

4. Record the current reading.

IS = _____________ (A)

5. Is this the same as the simulated and calculated value? ________ (YES or NO)

6. Measure and record the branch currents:

IR = ________ (A) IC = ________(A) IL = ________(A)

Are the current readings the same as your calculated and simulated values?

(Circle your answer)

YES NO

If you answered NO, explain why you think they differ.

7. Repeat Steps 2 through 6 with the frequency generator set to output at 1000 Hz. IS = ______________(A)

IR = ________ (A) IC = ________(A) IL = ________(A)

Are the current readings the same as your calculated and simulated values?

(Circle your answer)

YES NO

If you answered NO, explain why you think they differ.

IV. TROUBLESHOOTING

Describe any problems encountered and how those problems were solved.

Function

Generator

V

S

= 2.5 V

RMS

C

=

1

µ

F

R

=

4

7

0

Ω

I

R

I

C

+

I

S

f = 550 Hz

I

L

L

=

4

7

m

H

R

L

AC

C = 1 µF

R = 470 Ω

IS

f = 550 Hz

IL

IR

IC

+

Function Generator

RL

L = 47 mH

VS = 2.5 VRMS