## Question

A Si diode (*p*-*n *junction) is connected to a resistor *R* and a biasing battery of variable voltage *V _{B}*. Assume that diode requires a maximum current of 1 mA to be above the knee point (0.7 V) of its

*V*-

*i*characteristic curve. Also assume that the voltage

*V*across the diode is independent of current above the knee point. If

*V*= 5

_{B}*V*, what should be the maximum value of

*R*so that the voltage

*V*is above the knee-point voltage?

### Solution

Let *V _{R}* and

*V*be the voltages across the resistor

*R*and the diode respectively. Then

.

.

For *R* to be maximum (*R _{max}*), the current

*i*should be minimum . Thus, by Ohm’s law

.

#### SIMILAR QUESTIONS

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