MCQ
A $5,0 V$ stabilized power supply is required to be designed using a $12 V$ DC power supply as input source. The maximum power rating of zener diode is $2.0 W$. The minimum value of resistance $R_s$ (in $\Omega$ ) connected in series with zener diode will be
  • A
    16.5
  • 17.5
  • C
    18.5
  • D
    15.5

Answer

Correct option: B.
17.5
(b) : Given, $P=2 W$
Let current is $i$.
$
2=5 i \quad(P=V i)
$
$
i=\frac{2}{5} A
$
Now, $\varepsilon=12=5+i R$
$
R=\frac{7}{i}=\frac{7 \times 5}{2}=17.5 \Omega
$
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