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14.Semiconductor Electronics
medium
A zener diode in the circuit shown has a knee current of $5\,mA$ and a maximum allowed power dissipation of $300\,mW$ . What are the minimum and maximum load currents that can be drawn safely from the circuit, keeping the output voltage $V_0$ constant at $6\,volts$ ?
A
$0\,mA,\,180\,mA$
B
$5\,mA,\,110\,mA$
C
$10\,mA,\,55\,mA$
D
$60\,mA,\,180\,mA$
Solution
Current from source is $\mathrm{I}=(9-6) / 50=.06 \mathrm{A}$
$=60 \mathrm{mA}$
Now, $ \mathrm{I}_{\mathrm{zmin}}=5 \mathrm{mA}$ and
${{\rm{I}}_{z\max }} = {{\rm{P}}_{\max }}/{\rm{Vz}} = 300{\rm{mW}}/6{\rm{V}} = 50{\rm{mA}}$
So, $I_{\text {Lmax }}=I-I_{\text {zmin }}=60 \mathrm{mA}-5 \mathrm{mA}=55 \mathrm{mA}$
and ${I_{Lmin}} = I – {I_{z\max }} = 60{\rm{mA}} – 50{\rm{mA}} = 10$ $\mathrm{m} \mathrm{A}$
Standard 12
Physics
