Semiconductor Electronics Materials Devices And Simple Circuits Ques 24
A zener diode, having breakdown voltage equal to $15$ $ V$, is used in a voltage regulator circuit shown in figure. The current through the diode is not provided.
[2011M]
(a) $10$ $ mA$
(b) $15$ $ mA$
(c) $20$ $ mA$
(d) $5$ $ mA$
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Answer:
Correct Answer: 24.(d)
Solution:
- (d) Voltage across zener diode is constant.
Current in a $1,\text{k}\Omega$ resistor,
(i) $1 k$ $ \Omega=\frac{15 V}{1 k \Omega}=15 $ $mA$
Current in a $250~\Omega$ resistor,
$(i) _{250 \Omega}=\frac{(20-15) V}{250 \Omega}=\frac{5 V}{250 \Omega} $
$=\frac{20}{1000} A=20$ $ mA $
$\therefore(i) _{\text{zener diode }}=(15-20)=5 $ $mA$ .
BETA
