A. channel area
B. channel voltage
C. channel current
D. channel variation
Answer: A
MESFETs are channel area modulation devices and they depend upon the capacitance of the Schottky barrier.
2. Gallium arsenide has _____ regions of operation.
A. two
B. three
C. four
D. five
Answer: B
Gallium arsenide devices have three regions of operation – cutoff, linear, and saturation.
3. Drain to source current is due to
A. flow of majority carriers from drain to source
B. flow of minority carriers from drain to source
C. flow of majority carriers from source to drain
D. flow of majority carriers from drain to source
Answer: D
The current Ids results due to the flow of electrons, the majority carrier from source to drain. Ids can be given as the ratio of charge induced in the channel to electron transit time.
4. Transit time can be given as the ratio of
A. channel length to velocity
B. electron distance to velocity
C. source length to velocity
D. drain length to velocity
Answer: A
The transit time is given as the ratio of channel length to velocity and the carrier velocity can be further given as the product of electric field and electron mobility.
5. The average potential is given as
A. Vgs – Vt
B. 0.5(Vgs – Vt)
C. 0.25(Vgs – Vt)
D. 2(Vgs – Vt)
Answer: B
The average potential difference between the gate and the channel (VgB. owing to the shape of the depletion layer can be given as 0.5(Vgs-Vt).
6. Average electric field is _______ to implant depth.
A. directly proportional
B. indirectly proportional
C. does not depend
D. exponentially dependent
Answer: B
The average electric field is indirectly proportional to implant depth and this electric field can be given as (Vgs-Vt)/a.
7. The range of kp in MESFET is
A. 0.1 to 1 mA/V2
B. 1 to 5 mA/V2
C. 0.1 to 0.5 mA/V2
D. 0 to 1 mA/V2
Answer: C
β is a common parameter used in MESFET and it is denoted by kp. Kp is in the order of 0.1 to 0.5 mA/V2.
8. The hyperbolic tangent function is used to describe the
A. channel conductance
B. channel length
C. channel strength
D. channel depth
Answer: A
The hyperbolic tangent function tanh(aVds) is used to describe the channel conductance at the low drain to source voltage Vds.
9. The magnitude of the depletion region decreases when
A. Vgs decreases
B. Vgs increases
C. Vds increases
D. Vds decreases
Answer: B
When the gate to source voltage Vgs increases, the magnitude of the depletion region beneath the gate decreases.
10. Current saturation occurs when
A. Vgs < Vt
B. Vgs > Vt
C. Vgs > Vds
D. Vgs = Vt
Answer: A
When Vgs < Vt the increase in the drain to source voltage above the saturation voltage leads to current saturation.
