ECET210 Week 2 iLab3 | Complete Solution

Laboratory Procedures
DeVry University
College of Engineering and Information Sciences

I.OBJECTIVES

1. To analyze a series AC circuit containing a capacitor (C) and a resistor (R) using Ohm’s Law and Kirchhoff’s Voltage Law.

1. To simulate the RC circuit and observe the voltage drops and current at different frequencies.
    
2. To build an RC circuit and measure voltage drops and current at different frequencies.

1. To prove that the power delivered by the source is equal to the sum total of power dissipated by all the resistors in the circuit.

II.        PARTS LIST

Equipment:

          IBM PC or compatible                       

                             Function generator

DMM (digital multimeter)

Parts:

            1 - 1 K Ω  Resistor                  1 - 100 nF Capacitor

Software:

                        MultiSim 11

III.       PROCEDURE

A.        Theoretical Analysis

1. Given the R & L series circuit in Figure 1, calculate the total equivalent impedance, ZT , of the circuit at frequencies, f = 1 kHz, 2kHz and 3 kHz and list the numbers obtained in Table 1.

Figure 1 – Series RC Circuit

Frequency (kHz)

Reactance  XC

         (Ω)

Total Circuit Impedance ZT

Rectangular Form

R + j XC

Magnitude

Angle

1

2

3

Table 1 – RC Circuit Calculated Impedance Values

1. Calculate and record the following quantities: 

Frequency (kHz)

IS (RMS) - (A)

Power Factor

Rectangular Form

Magnitude

Angle

1

2

3

Table 2 – RC Circuit Calculated Current Values

Frequency (kHz)

VC (RMS) – (Volts)

Rectangular Form

Magnitude

Angle

1

2

3

Table 3 – RC Circuit Calculated Capacitor Voltage Values

Frequency (kHz)

VR (RMS) – (Volts)

{VC + VR}(RMS)  

           (Volts)

Rectangular Form

Magnitude

Angle

1

2

3

Table 4 – RL Circuit Calculated Voltage Values

1. Does the sum of the two voltage drops in Table 4 above equal 1 VRMS ?

                                                         (YES or NO)    

Explain your answer.

1. Calculate the power dissipated in the series resistor of  this circuit and also the power supplied by the source:

Frequency (kHz)

PR

(W)

PS

(W)

1

2

3

Table 5 - Source Power and Power Dissipation

B.        MultiSim Simulation and Circuit Calculations

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

Figure 2 – MultiSim RC Circuit with Instrumentation

Note# 1: The Multisim AC Power Source has the facility to choose RMS value (2.5 V) for the voltage in addition to the frequency and the phase of your choice.

Note# 2: You could choose any one frequency (1kHz, 2 kHz or 3 kHz) for the source from section A. The figure below shows source frequency as 1 kHz, for example.

1. Set the RMS value to 2.5 V and select one of the frequencies (1 kHz, 2 kHz, or 3 kHz) used in Section A.
    
2. Activate the simulation and record the voltage and current reading in Table 5.

Frequency (kHz)

IS (RMS)
(Amps)

VC (RMS)
(Volts)

  VR (RMS)   (Volts)

Table 5 - MultiSim Simulation Results

1. Do the (simulated) voltage and the current values in Table 5 agree with those obtained in Tables, 2, 3 and 4 of Part A? (Circle your answer)   

                                                            YES             NO

1. Remove the DMMs from the circuit and attach the wattmeter as shown below:

Figure 3 - AC Power Measurement with Wattmeter

1. Turn the simulator ON and record the power measurements in Table 6.

Frequency

(kHz)

Source Power, PS

(Watts)

Power Factor

Table 6 - Power Measurement Readings

1. Do the numbers in Tables  6 and 2 agree?

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

C.        Construction of a Series R C Circuit on a proto board and Measurement of Circuit Characteristics

1. Construct the circuit in Figure 1.
2. Set the function generator voltage to 2.5 V RMS.  Set the frequency to the same value used in the simulator experiment.
3. Set DMM to measure AC current and make the appropriate connections. Switch the function generator power ON.
4.  Record the current reading.       

IS = _____________ (A)

1.  Is this the same as the simulated value and the calculated value? ________ (YES or NO)
2. Switch OFF the AC input power. Remove the DMM and reconfigure it to measure voltages.  Reconnect the circuit and apply power. Measure the voltage across C and R one at a time.
3.  Record these voltages.

VC = ________    (V)      VR  = ________(V)       

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

 __________ (YES or NO)

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

IV.       TROUBLESHOOTING

Describe any problems encountered and how those problems were solved.