A PN-junction diode has a reverse saturation current of 30 μA at a temperature, of 125°C. At the same temperature, find the dynamic resistance for 0.2 V bias in forward and reverse directions.

Question

Accepted Answer

Given The reverse saturation current, [latex]I_{o} = 30 × 10 ^{– 6} A and V = 0.2 V[/latex]

We know that the dynamic resistance [latex]=\frac{\eta V_{T} }{I_{0}e^{V/\eta V_{T} } }[/latex]

Here, η = 1 for germanium and [latex]V_{T}=\frac{T}{11,600} =\frac{125+273}{11,600} =34.3 mV[/latex]

Therefore, forward dynamic resistance [latex]r_{f}=\frac{34.3 imes 10^{-3} }{30 imes 10^{-6}(e^{0.2/34.3 imes 10^{-3} } ) }=3.356 \Omega [/latex]

Reverse dynamic resistance, [latex]r_{r}=\frac{ \eta V_{T} }{I_{0}e^{-V/\eta V_{T} } } =\frac{34.3 imes 10^{-3} }{30 imes 10^{-6}(e^{-0.2/34.3 imes 10^{-3} } ) } =389.5k\Omega [/latex]

Question 4.19: A PN-junction diode has a reverse saturation current of 30 μ...

Related Answered Questions