Question

1)

An NPN BJT operating in the cutoff region has :

Select one:

a. Vbe > 0 and Vbc > 0

b. Vbe < 0 and Vbc < 0

c. Vbe < 0 and Vbc > 0

d. Vbe > 0 and Vbc < 0

e. None of these

2)

In the forward-active region, current flows into the base of an NPN BJT.

Select one:

True

False

3) If the DC base-emitter junction voltage, Vbe, for an NPN BJT in the forward-active region is equal to 677 mV, and the DC collector-to-emitter voltage is Vce = 12.4 V, then what is the collector current flowing in this BJT, Ic, in milliamps? Assume that the saturation current for this BJT, Is, is equal to 44 fA. (Note that 1 fA = 1 femtoamp = 1 x 10^-15 A.) Include the effects of base-width modulation, and use an Early Voltage of 29 V. Also assume that the thermal voltage is equal to Vt = kt/q = 26mV. Since Ic is very sensitive to small changes in Vbe, be sure to use Vbe to the nearest millivolt when calculating your answer!

4)

Which of the following is true in modern bipolar junction transistors?

Select one:

a. The minority carrier concentration in the base decreases exponentially from the emitter to the collector

b. The base is kept narrow to minimize recombination in the base

c. Carriers diffuse across the base and are collected by the emitter

d. The base doping is much higher than the emitter doping to minimize the number of carriers injected from the base into the emitter

e. None of these

5)

An NPN BJT with Vbe > 0 and Vbc < 0 is operating in the reverse-active region.

Select one:

True

False

Answer 1