A silicon p-n junction diode is forward biased by a 2 V battery connected through a series resistor of 10 Ω. The current through the diode will be
(Assume the threshold voltage for a silicon diode is 0.7 V)
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 0.13 A
A silicon diode begins to conduct only after the forward voltage exceeds its threshold voltage, and about 0.7 V then stays across the diode. The rest of the battery voltage appears across the series resistor, which sets the current.
\( \displaystyle V_R = V - V_{\mathrm{th}} = 2\,\mathrm{V} - 0.7\,\mathrm{V} = 1.3\,\mathrm{V} \)
\( \displaystyle I = \frac{V_R}{R} = \frac{1.3\,\mathrm{V}}{10\,\Omega} \)
\( \displaystyle I = 0.13\,\mathrm{A} \)