Problem Set Zener Diodes
Problem Set Zener Diodes
Problem Set Zener Diodes
=
Z S
Z IN
Z
R R
V V
I and V 424 . 8 = + =
Z Z Z OUT
V R I V .
Question 2
(b) V 0 . 10
) (
=
MIN S
V and V 0 . 20
) (
=
MAX S
V . Using the results of Question 1 we get
mA 294 . 5
) (
) (
=
+
=
Z S
Z MIN S
MIN Z
R R
V V
I giving V 306 . 8
) ( ) (
= + =
Z Z MIN Z MIN OUT
V R I V . Similarly,
V 894 . 8
) (
=
MAX OUT
V . The variation in the output is V 306 8 894 8 . . or V 588 . 0 or % 1 . 7 Note
that the input variation is V 0 . 10 or % 0 . 100 .
Question 3
(b) Replace the Zener diode with its equivalent circuit:
R
S
V
IN
V
OUT
V
Z
R
Z
R
L
N
Sum the currents leaving the node N to get 0 = +
L
OUT
Z
Z OUT
S
IN OUT
R
V
R
V V
R
V V
. Now solve for the
output voltage V 465 . 8
1 1 1
=
+ +
+
=
L Z S
Z
Z
S
IN
R R R
R
V
R
V
OUT
V . The Zener current is mA 267 . 13 =
=
Z
Z OUT
Z
R
V V
I .