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John Kurien
EEL3304C: Lab 2
6690-5410
2/21/2006
I. Objectives
The objectives of the experiment
DSO to characterize a diode, and
characteristics in various diode
full-wave rectifier, and a diode
were to learn how to use the Tektronix
to investigate the diode
circuits (i.e. half-wave rectifier,
regulator).
II. Equipment
The following equipment was used:
 National Instruments ELVIS
 Textronix TDS2024 DSO
 1N4148 Switching Diode


1N4732 Zener Diode
Various Capacitors and
resistors
III. Prelab & Design
The pre-lab data acquired about the 1N4148 switch diode and 1N4732
Zener diode were respectively taken from the following sources:
http://ist-socrates.berkeley.edu/~physlab/bsc/PDFFiles/1N4148.pdf
http://www.datasheetarchive.com/semiconductors/pdfdatasheet.php?Datashe
et=57004 (Jinan Gude Electronics Device)
The following data values were recorded:
1N4148
1N4732
VF
1.0 V
VZ
4.7 V
IZT
53 mA
IZK
1 mA
rZ
8 Ω
Table 1: Recorded diode values
Design a Half Wave Rectifier
The following circuit was used to design the half wave rectifier.
Figure 1: Half Wave Rectifier Circuit
The input signal used was a 5 V peak-to-peak sine wave at 1 kHz and
10kHz. The expected outputs are shown below:
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Figure 2: 1 kHz Output
Figure 3: 10 kHz Output
Notice that the signals do not change except for their periods. Also
the output voltage (green) is slightly lower that the input voltage
(red). The input was 2.5 V peak and the expected output was 1.5 V due
to the drop from VF. Therefore it is reasonable to say that the
frequency does not affect the output voltage.
A general outline of the procedure established to conduct the
experiment was:
1. Build circuit
2. Measure input
a. Take picture
3. Measure output
a. Take picture
4. Repeat for 1 kHz, 5 kHz, and 10 kHz
Design a Peak Rectifier
The following circuit was used to design the peak rectifier:
Figure 4: Peak Rectifier
Since the ripple of the circuit is defined as
Vr
using the following
Vp
equation we try to obtain a 10% ripple:
Vr 
Vp
fCR
(Equation 1)
therefore fCR must equal 10.
(10k)(C)(1k)=10 => C = 1 μF
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The predicted output was as follows:
Figure 5: 1 kHz Output
Figure 6: 10 kHz Output
VR for 1 kHz was calculated:
VR = (Ripple)(VP) = (0.1)(2.5 V) = 250 mV
10 kHz requires a different equation:
T
Vr
 1  e CR
Vp
(Equation 2)
1ms
(1F )(1k )
which results in: 1  e
 63.2121%
therefore Vr = (0.632121)(2.5 V) = 1.5803 V = 1580 mV
A general outline of the procedure established to conduct the
experiment was:
1. Build circuit
2. Use 10 kHz/1 kHz for C = 1 μF
3. Record values
4. Take picture of all graphs
5. Measure the ripple and calculate how close it is
Design a Zener Diode Regulator
The following circuit was used to design the Zener diode regulator:
Figure 7: Zener Diode Regulator
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VS varied from 7 V to 15 V and IL varied from 0 to 30 mA. VZO was
calculated by:
VZ = VZO + rZIZ
(Equation 3)
4.7 V = VZO + (8 Ω)(23 mA)
VZO = 4.276 V
R was calculated by appling KVL:
-7 V + (53 mA)R + 4.276 + (8 Ω)(23 mA) = 0
R = 47.9245 Ω ≈ 48 Ω
The worst-case scenario for the power dissipation through the Zener
diode and R is when IL is zero and VS is 15 V.
V 2 (15  4.7) 2
PR 

 2.21369W
R
47.9245
PZ  VI  (4.7V )(214.921mA)  1.01013  1.01W
(Equation 4)
(Equation 5)
(214.921 was calculated by applying Ohm’s Law to the resistor R.)
LiR 
 V   V 
VO
r
 z  %change   Z   S 
VS rz  R
 VS   VZ 
 8V 
%change  (0.14305)
  0.243489  24.3489%
 4.7V 
 rR 
 V   I 
V
LoR  O   z   %change   Z   L 
I L
 rz  R 
 I L   VZ 
 30mA 
%change  (6.8556)
  4.3759%
 4.7V 
Summarized results:
Variable
VZO
R
PR
PZ
Line Regulation
Line Regulation %
Load Regulation
Load Regulation %
Table 2: Summarized
(Equation 6)
(Equation 7)
Value
4.276 V
47.9245 Ω
2.21369 W
1.01013 W
0.14305 V/V
24.3489%
6.8556 V/A
4.3759%
Zener regulator values
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IV. Experiment
Diode Forward Characteristics
The lab deviated slightly from the handout. Initial recordings for the
switching and Zener diode were recorded with the Textronix 576 Curve
Tracer as per the instructor. Later recordings were taken by the
Textronix DSO.
Switching Diode
Zener Diode
Voltage
Current
Voltage
Current
0.7 V
5.4 mA
4.8 V
53 mA
0.72 V
5 mA
4.7 V
53 mA
Table 3: Measured diode values
Using the data collected the value of rz was calculated:
1
rz
4.8V  4.7V
1
 3.33  Slope   0.3 -1
30mA
rz
Slope=
(Equation 8)
(Because this was performed on the Tektronix 576 a picture could not be
obtained of the curve.)
The data obtained from the same setup on the Textronix TDS2024 DSO was
used to extrapolate the data to determine IS and n.
Voltage (V)
Current (mA)
0.000
0.009
0.040
0.008
0.080
0.008
0.119
0.008
0.159
0.009
0.199
0.009
0.239
0.009
0.278
0.009
0.318
0.011
0.357
0.014
0.396
0.021
0.433
0.036
0.475
0.077
0.514
0.162
0.550
0.321
0.588
0.660
0.628
1.342
0.667
2.596
0.702
4.393
0.728
6.239
0.751
8.286
0.769
10.099
Table 4: Zener diode I-V data
The linear and logarithmic graphs are shown:
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Figure 8: Linear I-V curve for the tested Zener Diode
Figure 9: Logarithmic I-V curve for the tested Zener Diode
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Zener Diode Properties
(Refer to figure 17 at the end of the paper to see extrapolation of the
linear region of the logarithmic plotting of the diode I-V values.)
Extrapolating the linear portion back to the current axis gives a value
of –0.075 mA. Thus IS is equal to 75 μA. Figure 9 gives a more
detailed and accurate plot actually taken by the DSO.
Since a decade of current change is defined by:
∆v = n x 60 mV
(Equation 9)
Values taken from the linear portion of the curve resulted in:
0.61 V-0.49 V = n x 60mV
n=2
Design a Half Wave Rectifier
The 1 kΩ resistor was measured at 0.97 kΩ. Each of the three tested
frequencies, 1 kHz, 5 kHz, and 10 kHz had a 0.6 V voltage drop across
the diode. Using Ohm’s Law the current for this circuit was:
icalc = (2.5 V – 0.6 V)/1000 Ω = 1.9 mA
(Equation 10)
The graphs are shown below:
Figure 10: Input and Output graphs for 1 kHz
Figure 11: Input and Output graphs for 5 kHz
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Figure 12: Input and Output graphs for 10 kHz
Design a Peak Rectifier
The values for the 1 kHz and 10 kHz waves are as follows:
1 kHz, 5 V Peak-Peak
10 kHz, 5 V Peak-Peak
R
0.97 kΩ
R
0.97 kΩ
C
0.97 μF
C
0.97 μF
Vr
740 mV
Vr
84 mV
Vp
1.28 V
Vp
1.02 V
Vr/Vp
0.578125
Vr/Vp
0.082353
Table 5: 1 kHz, 5 V Peak-Peak
Table 6: 10 kHz, 5 V Peak-Peak
Vr/Vp for the 1 kHz was calculated as follows (as was the 10 kHz):
Vr/Vp = 84 mV/1.02 V=0.082353
The graphs for the peak rectifiers showing Vr and Vp are below:
Figure 13: 1 kHz Vp
[Note to the reader: During the transfer of files the 1 kHz Vr file
became corrupt. The file was unrecoverable.]
Figure 14: 1 kHz Vr
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Figure 15: 10 kHz Vp
Figure 16: 10 kHz Vr
Design a Zener Diode Regulator
The circuit in Figure 7 was constructed. The 48-Ω resistor was
measured at 48 Ω. The value for RL was given by our lab instructor and
was told to be 160 Ω. Since a 160-Ω resistor was unavailable, a 151 Ω
and 11-Ω resistor were placed in series to created a measured value of
162-Ω. Again the same worst-case situation was used for the power
dissipation across R and the Zener diode.
Values were measured for the Line and Load Regulation calculations.
For the Line Regulation the actually values could be recorded for ΔVZ/VZ
and ΔVZ/IL. The values were taken at nominal load current and nominal
input voltage. For example the Load Regulation was calculated as
follows:
VZ 4.747  4.8581

 3.7033
I L
30mA  0
(Equation 11)
The percentages were calculated just as in Prelab.
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The following table summarizes the results:
Zener Diode Values
Voltage
Value
Power Dissipation
VR
10.10 V
2.12521 W
VZO
5.1 V
1.0302 W
Variable
Value
PR
2.12521 W
PZ
1.0302 W
Line Regulation
0.037464
Line Regulation %
5.8767%
Load Regulation
3.7033
Load Regulation %
2.1784%
Table 7: Measured Values (Calculated the same as in Prelab)
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V. Discussion
Diode Forward Characteristics
IS was extrapolated by hand on semi log paper in Figure 17.
Inaccuracies may be present due to human error. The value of n was
exactly 2 and was calculated using the values from the picture taken by
the DSO. The value of rZ was extremely far from the Prelab value as
stated in the next section.
Zener Diode Properties
The Zener diode was warm to the touch but did not feel like it was
extremely hot to the point of burns. It got warmer as the voltage
increased. The value recorded for rZ was 3.33Ω. Percentage error for
this value is below:
TheoreticalValue  ActualValue
TheoreticalValue
(100) 
8  3.33
8
(100)  58.375%
(Equation 12)
As it can be seen the percentage error for the diode resistance was
extremely high. This was due to the use of the Textonix 576 Curve
Tracer, which was not very accurate in presenting values.
Design a Half Wave Rectifier
As Figures 10 through 12 show, the frequency of the input does not
affect the output. The only change was the period between each graph
as expected. Also the voltage drop due to the diode was the same with
each (0.6 V).
Design a Peak Rectifier
The percentage errors for Vr were above 50 percent for both frequencies.
This is because the Vp value was not the same as calculated in Prelab.
The value that does matter however is the ratio of the two identifying
the ripple. For 1 kHz the percentage error was only about 8.54% and
for 10 kHz it was about 17.65%. The error is because of the increased
time for the capacitor to discharge. The 10 kHz signal discharge time
was shorter as opposed to a longer discharge time for the 1 kHz. Thus
the measurements taken for the 10 kHz signal were more sensitive to
small inaccuracies in measurements. Other factors such as nonidealities in resistor and capacitor values or capacitance of the
oscilloscope seem to be negligible.
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Design a Zener Diode Regulator
The table below displays the theoretical values, recorded values, and
percentage errors for the Zener diode regulator:
Variable
Theoretical
Recorded
Percentage Error
PR
2.21369 W
2.12521 W
3.9969%
PZ
1.01013 W
1.0302 W
1.9869%
Line Regulation
0.14305 V/V
0.037464
73.8106%
Line Regulation %
24.3489%
5.8767%
75.8646%
Load Regulation
6.8556 V/A
3.7033
45.9814%
Load Regulation %
4.3759%
2.1784%
50.2182%
Table 8: Zener diode regulator percentage errors
The power dissipations had minimal percentage errors while large errors
were seen in both the line and load regulations. This was because the
actual value of rz was extremely far from the Prelab value calculated.
The value for rz was incorrect by over 50 percent, which altered the
results seen in the line and load regulation by an extreme amount.
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VI. Summary
Knowledge of switching diodes and Zener diodes was obtained. Not all
diode characteristics were experimentally verified. Some results were
not obtained as desired because rz was not accurate, and a portion of
the lab used the curve tracer, which was not very accurate. A better
understanding of how to operate the Textronix TDS2024 DSO was also
gained.
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