1
GATE ECE 2014 Set 4
Numerical
+2
-0
Consider two BJT's biased at the same collector current with area A1 = 0.2 μm × 0.2 μm and A2 = 300 μm × 300 μm. Assuming that all other device parameters are identical, kT/q = 26 mV, the intrinsic carrier concentration is 1 × 1010 cm-3, and q = 1.6 × 10-19 C, the difference between the base-emitter voltages (in mV) of the two BJT's (i.e., VBE1 – VBE2) is___________.
2
GATE ECE 2011
+2
-0.6
The channel resistance of an N-channel JFET shown in the figure below is 600 W when the full channel thickness (tch) of 10 μm is available for conduction. The built-in voltage of the gate P+N junction (Vbi) is -1 V. When the gate to source voltage (VGS) is 0 V, the channel is depleted by 1 μm on each side due to the built in voltage and hence the thickness available for conduction is only 8 μm The channel resistance when VGS = -3 V is
A
360 Ω
B
917 Ω
C
1000 Ω
D
3000 Ω
3
GATE ECE 2011
+2
-0.6
The channel resistance of an N-channel JFET shown in the figure below is 600 W when the full channel thickness (tch) of 10 μm is available for conduction. The built-in voltage of the gate P+N junction (Vbi) is -1 V. When the gate to source voltage (VGS) is 0 V, the channel is depleted by 1 μm on each side due to the built in voltage and hence the thickness available for conduction is only 8 μm The channel resistance when VGS = 0 V is
A
480 Ω
B
600 Ω
C
750 Ω
D
1000 Ω
4
GATE ECE 2010
+2
-0.6
In a uniformly doped BJT, assume that NE, NB and NC are the emitter, base and collector dopings in atoms/cm3, respectively. If the emitter injection efficiency of the BJT is close unity, which one of the following conditions is TRUE?
A
NE = NB = NC
B
NE $$\gg$$ NB and NB > NC
C
NE = NB and NB < NC
D
NE < NB < NC
EXAM MAP
Medical
NEET