580
21 Diodes
(a)
R L
V in
R 1
V out
(b)
(c)
(d)
Fig. 21.65 a Circuit diagram of a voltage regulator, b diode characteristic (n = 1). The vertical dashed lines show the
operation conditions for R L = 2 k and U E = 5 and 9 V and thus the principle of voltage stabilization. c Output versus
input voltage and d stability (differential voltage ratio α, see text) for input voltage between 5 and 9 V
Fig. 21.66 Characteristics
of a field of Zener diodes
(at room temperature)
80
70
60
50
40
30
20
10
0
0
1
3
4
5
6
2
7
8
9
1 0
5mA
Z4
Z7
Z8
Z6
Z3
Z5
21.5.4 Zener Diodes
A Zener diode is designed to have a defined breakdown voltage. Zener diodes are available with a
number of different standard breakdown voltages. Their characteristic is shown for reverse bias with
the current shown positive. The characteristics of various Zener diodes for different breakdown voltages
are shown in Fig. 21.66.
21 Diodes
(a)
R L
V in
R 1
V out
(b)
(c)
(d)
Fig. 21.65 a Circuit diagram of a voltage regulator, b diode characteristic (n = 1). The vertical dashed lines show the
operation conditions for R L = 2 k and U E = 5 and 9 V and thus the principle of voltage stabilization. c Output versus
input voltage and d stability (differential voltage ratio α, see text) for input voltage between 5 and 9 V
Fig. 21.66 Characteristics
of a field of Zener diodes
(at room temperature)
80
70
60
50
40
30
20
10
0
0
1
3
4
5
6
2
7
8
9
1 0
5mA
Z4
Z7
Z8
Z6
Z3
Z5
21.5.4 Zener Diodes
A Zener diode is designed to have a defined breakdown voltage. Zener diodes are available with a
number of different standard breakdown voltages. Their characteristic is shown for reverse bias with
the current shown positive. The characteristics of various Zener diodes for different breakdown voltages
are shown in Fig. 21.66.