Which resistance is offered by the diode in forward direction above the barrier voltage?
Which resistance is offered by the diode in forward direction above the barrier voltage ?
a. Bulk Resistance
b. Junction Resistance
c. Dynamic Resistance
d. Reverse DC Resistance
Correct Answer: a. Bulk Resistance
Bulk resistance is the sum of resistance values of P & N type semiconductor materials. By having a glance over the following figure, it is obvious that
rB = rp + rN
Because of its minute value, bulk resistance can also be expressed as,
rB = ( VF - VB ) / IF
When the value of current is very large, the diode offers the resistance above the barrier voltage in forward direction.
On the contrary, junction resistance solely depends on the magnitude of forward DC current & hence ultimately known as 'Variable Resistance'. Dynamic resistance is almost equal to junction resistance for negligible values of rB and IF. Apart from these, reverse DC resistance is offered in case of reverse voltage corresponding to reverse current absolutely in reverse direction.