BME 153 Lab 4
Lab 4 – Capacitors, Inductors and the Oscilloscope
Nigel Chou Shijie
Lab Partner: Tim Liu
Section 1
October 10, 2007
I have adhered to the Duke Community Standard in completing this assignment.
Objectives
The objective of this lab is, firstly, to learn to use the oscilloscope and the function generator to find
the amplitude and period of AC signals and the phase difference between two AC signals. Secondly, we
learned to measure capacitance and inductance using a LCR meter.
Thirdly, learned how to find the
amplitude and phase difference of the voltage across resistors, capacitors and inductors with reference to the
source voltage.
Apparatus
•
LCR Meter
•
Fluke 45 Dual Display Digital Multimeter (DMM)
•
BK Precision 1652 Triple Output Power supply
•
Tektronic TDS 1012 Digital Storage Oscilloscope
•
TGS 50 Signal generator
•
Resistors, capacitor and inductor
Procedure
The procedure listed in the lab manual was followed with no deviation.
Data and Calculations
Resistor circuit with AC Source
The voltages were calculated as follows:
a
R
V
V
=
2
and
b
R
V
V
=
4
.
b
a
R
V
V
V

=
3
a
in
R
V
V
V

=
1
b
in
R
V
V
V

=
5
The current was calculated by taking the voltage across each resistor and dividing by its resistance:
R
V
I
=
The RMS voltage and current were obtained by taking the amplitudes and dividing by square root of 2:
2
of
Amplitude
V
V
RMS
=
and
2
of
Amplitude
I
I
RMS
=
The average power was obtained from the RMS values of Voltage and/or Current according to:
R
V
P
RMS
2
)
(
=
or
R
I
P
RMS
2
)
(
=
or
)
)(
(
RMS
RMS
I
V
P
=
All three methods give the same values.
1
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
BME 153 Lab 4
Capacitors and inductors
The % difference of the capacitance and inductance of circuit elements is calculated by:
%
100
Value
Nominal
Value
Nominal

value
Measured
diff
%
×
=
The phase shift of the voltages are calculated by:
π
2
Period
shift
Time
shift
Phase
×
=
The AC and DC currents are calculated from the voltage measured by the DMM by:
R
V
I
=
Results
PeaktoPeak Voltage:
6.00 V
Frequency:
1.002 kHz
V
in
:
3.00 sin(2004πt)
V
a
:
1.81 sin(2004πt)
V
b
:
1.66 sin(2004πt)
Table 1 :
Current and Voltage across
different resistors (R
1
to R
5
) of Figure 1.
Resistor
Resistance
(
Ω
)
Voltage (V)
V
rms
(V)
Current
(mA)
I
rms
(mA)
Power
dissipated
(mW)
R1
1000
1.19 sin(2004πt)
0.841
1.19 sin(2004πt)
0.841
0.708
R2
2000
1.81 sin(2004πt)
1.28
0.905 sin(2004πt)
0.640
0.819
R3
470
0.15 sin(2004πt)
0.106
0.319 sin(2004πt)
0.226
0.0239
R4
1500
1.66 sin(2004πt)
1.17
1.11 sin(2004πt)
0.782
0.919
R5
1800
1.34 sin(2004πt)
0.947
0.744 sin(2004πt)
0.526
0.499
Total:
2.968
Table 2 :
Measured and nominal resistances of capacitor and inductor in circuits of Figure 2 and 3
Circuit Element
Nominal Value
Value measured
with LCR Meter
Percent Difference
Capacitor (nF)
220
207.1
5.86%
Inductor (mH)
4.7
4.493
4.40%
Table 3 :
Voltages and phase angles across the resistors in the circuit from Figure 2 and 3
Figure 2 (AC)
Figure 3 (AC)
V
in
(RMS) (V)
1.77
1.77
V
a
(RMS)
(V)
0.636
1.15
V
in
 V
a
(V)
1.13
0.622
This is the end of the preview.
Sign up
to
access the rest of the document.
 Fall '07
 MALKIN
 Alternating Current, Oscilloscope, Electronic test equipment

Click to edit the document details