EE 213 Electrical Circuits Laboratory
Fall 2015
EXPERIMENT 5
CAPACITORS AND INDUCTORS
Objectives
In this experiment you will learn about
 Terminal characteristics, parallel and series connections of linear capacitors and inductors.
 Capacitance and inductance measurement methods.
Preliminary work
1. Review the notes “Introduction to Circuits”.
PART I: CAPACITOR
An actual capacitor can be modeled by an ideal capacitor in parallel with a resistor, which is illustrated in Fig.1
The conductance G in the given model represents the (leakage) loss of the capacitor. As G is usually quite small
it will be neglected in this experiment.
C
i
+
v
–
G
Figure 1
2. Consider the circuit of Fig. 2. Find the capacitance of the capacitor in terms of the measured current and
voltage values (rms values) and the angular frequency .
Figure 2
3. Consider the circuit of Fig. 3.
a. Find the expressions for charge q and the capacitance of the capacitor C in terms of V2 and VC.
b. How can q-v characteristics be obtained on DSO using this setup?
c. Verify your methodology by obtaining q-v characteristics of 220 F capacitor in simulation.
Figure 3
EE 213 Electrical Circuits Laboratory
Fall 2015
PART II: INDUCTOR
An actual inductor can be modeled as in Fig. 4 where the resistance r represents the resistance of the turns of
the coil.
i
L
+
r
v
–
Figure 4
4. How can the resistance of turns, r, be measured?
5. Replace the capacitor in Fig. 2 by a coil with an inductance value of L. Find L in terms of the measured
(rms) current and voltage values, the angular frequency  and the resistance r.
6. Consider the circuit of Fig. 5.
a. Find the expressions for flux  and the inductance L of the coil in terms of V2 and VR.
b. How can -i characteristics be obtained on DSO using this setup?
c. Verify your methodology by obtaining -i characteristics of 0.1H inductor in simulation.
- VR
+
Figure 5
Note for Simulations: If you are using LTSpice for simulations, please choose the simulation stop time such
that it covers only one or two cycles of the sinusoidal input. For other simulation software, you may
try increasing the frequency of the input signal for observing a better (at least linear) q-v or -i
characteristic.
Equipment List






Multimeter
Digital Storage Oscilloscope
Function/Arbitrary Waveform Generator
Capacitors (0.47 F, 0.1 F, 10 nF, 100 F, 220 F)
Inductors (0.1 H x 2)
Resistors (100 , 1 k, 100 k)
EE 213 Electrical Circuits Laboratory
Fall 2015
Experimental Work
1. Adjust the signal generator to 500 Hz, 6V peak and apply the signal to a capacitor C of 0.47 F nominal
capacitance value. Measure the AC current through and AC voltage across the capacitor using a multimeter
and determine its capacitance (Fig. 2).
2. Setup the circuit of Fig. 3 and apply 𝒗𝒊𝒏 (𝒕) = 𝟏𝟎𝒔𝒊𝒏(𝟐𝟎𝟎𝒕) 𝑽.
a. Obtain and plot q-v characteristics of the capacitor C of 220 F nominal value and determine its
capacitance.
b. Connect a capacitor of 100 F nominal capacitance value in parallel with C. Find the equivalent
capacitance using the new q-v characteristics.
c. Connect a capacitor of 100 F nominal capacitance value in series with C. Find the equivalent
capacitance using the new q-v characteristics.
d. Compare the results in parts (a), (b) and (c) and comment on the simulation results.
3. Label the coil with wooden box as 𝐿1 and the smaller dimensions as 𝐿2 . Repeat part 1 for both coils to
determine the inductance values. Use a 1 k resistor in series with the inductor for protection. Note that
the resistance of turns should be measured using a multimeter and you should indicate both the resistance
and the inductance values.
4. Setup the circuit of Fig. 5 and use the floating output of Advance Instruments Signal Generator for
𝒗𝒊𝒏 (𝒕) = 𝟏𝟎𝒔𝒊𝒏(𝟐𝒇𝒕) 𝑽, 𝒇 = 𝟓 𝒌𝑯𝒛.
a. Obtain and plot -i characteristics of the coil 𝐿2 and determine its inductance.
b. Connect the coil 𝐿1 in parallel with 𝐿2 . Find the equivalent inductance using the new -i characteristics.
c. Connect the coil 𝐿1 in series with 𝐿2 . Find the equivalent inductance using the new -i characteristics.
d. Compare the results in parts (a), (b) and (c) and comment on the simulation results.
e. Explain the reason for the use of Advance Signal Generator.