Science - Physics - Electricity and Electronics - 16 Diodes, Part 2
(P1377900)
16.1 The Characteristic Curve of Zener Diodes
Experiment by: MAGNETISM
Printed: Jan 10, 2011 1:12:18 PM
interTESS (Version 10.03 B132, Export 1678)
Task
Task
How do Zener diodes differ from normal rectifier diodes?
Investigate the relationship between current and voltage for a Zener diode in forward and reverse
direction.
Use the space below for your own notes.
Logged in as a teacher you will find a button below for additional information.
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Material
Material
Material from "Student equipment set electricity/electronics 1" (Order No.
05600.88) and Material from "Student equipment set electricity/electronics 2"
(Order No. 05601.88)
Position No.
Material
Order No. Quantity
1
Connector, straight, module SB
05601.01
3
2
Connector, angled, module SB
05601.02
3
3
Connector, T-shaped, module SB
05601.03
2
4
Connector, interrupted, module SB
05601.04
2
5
Connector, straight with socket, module SB
05601.11
1
6
Connector, angled with socket, module SB
05601.12
1
7
Resistor 50 Ohm, SB
05612.50
1
8
Resistor 100 Ohm, SB
05613.10
2
9
Z-diode, ZF 4.7, SB
05652.00
1
10
Connecting cord, 32 A, 250 mm, red
07360.01
1
11
Connecting cord, 32 A, 250 mm, blue
07360.04
1
12
Connecting cord, 32 A, 500 mm, red
07361.01
2
13
Connecting cord, 32 A, 500 mm, blue
07361.04
2
14
Multi-range meter, analogue
07028.01
2
15
Power Supply, 0...12 V DC/ 6 V, 12 V AC
13505.93
1
Additional Material
Material required for the experiment
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Setup
Setup
First experiment
Set up the circuit according to the schematic diagram 1 as shown in Fig. 1 and Fig. 2. Connect
the Zener diode in forward direction. Select a measurement range of 1 V- and 30 mA-. Make sure
that the polarity on the meters is correct and that the meters are connected properly.
schematic diagram 1
Fig. 1
Fig. 2
Second experiment
Set up the circuit according to the schematic diagram 2 as shown in Fig. 3 and Fig. 4.
Note: Make sure to change the polarity of the Zener diode. Switch the measurement range for
the voltage to 10 V-.
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schematic diagram 2
Fig. 3
Fig. 4
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Action
Action
First experiment
• Switch on the power supply unit. Increase the voltage UP on the power supply unit from 0 V
to 10 V in increments of 1 V. Measure both forward voltage UF and forward current IF. Enter
the measurements in Table 1 on the Results page.
• Switch off the power supply unit.
Second experiment
• Switch on the power supply unit and increase the voltage UP from 0 V to 10 V in increments
of 1 V once again. Measure both reverse voltage UR and reverse current IR. Since you inverted
the Zener diode polarity, you will have to enter the values measured as negative values in
Table 2 on the Results page.
• Switch off the power supply unit.
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Results
Results
Table 1
Voltage level on
power supply unit
Forward voltage Forward current
UF in V
IF in mA
0
nnnnnnnnnn
nnnnnnnnnn
1
nnnnnnnnnn
nnnnnnnnnn
2
nnnnnnnnnn
nnnnnnnnnn
3
nnnnnnnnnn
nnnnnnnnnn
4
nnnnnnnnnn
nnnnnnnnnn
5
nnnnnnnnnn
nnnnnnnnnn
6
nnnnnnnnnn
nnnnnnnnnn
7
nnnnnnnnnn
nnnnnnnnnn
8
nnnnnnnnnn
nnnnnnnnnn
9
nnnnnnnnnn
nnnnnnnnnn
10
nnnnnnnnnn
nnnnnnnnnn
UP in V
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Table 2
Voltage level on
Reverse voltage
Reverse current
power supply unit
UR in V
IR in mA
UP in V
(with negative sign) (with negative sign)
0
nnnnnnnnnn
nnnnnnnnnn
1
nnnnnnnnnn
nnnnnnnnnn
2
nnnnnnnnnn
nnnnnnnnnn
3
nnnnnnnnnn
nnnnnnnnnn
4
nnnnnnnnnn
nnnnnnnnnn
5
nnnnnnnnnn
nnnnnnnnnn
6
nnnnnnnnnn
nnnnnnnnnn
7
nnnnnnnnnn
nnnnnnnnnn
8
nnnnnnnnnn
nnnnnnnnnn
9
nnnnnnnnnn
nnnnnnnnnn
10
nnnnnnnnnn
nnnnnnnnnn
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Evaluation
Evaluation
Question 1:
Describe the behaviour of a Zener diode in a circuit. Use the term breakdown voltage in your
explanation. Breakdown voltage is the voltage at which a diode connected in reverse direction
loses its blocking ability.
Question 2:
How do Zener diodes differ from normal rectifier diodes?
Question 3:
What purpose does the multiplier R3 serve?
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Question 4:
Look at the characteristic curve in Diagram 1 on the Results page. The left arm of the graph
represents the voltage UR and the lower arm the current IR (the minus signs for both arms are just
for the technical realisation of displaying the graph). Determine the change in voltage in the reverse
direction when the current is increased from 20 mA to 30 mA. How can this characteristic of
Zener diodes be used in practice?
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