A. Vin = Vt
B. Vout = Vt
C. Vin = Vout
D. Vout is lesser than Vin
Answer: C
The point at which Vout = Vin, is denoted as Vinv. The transfer characteristic and Vinv can be shifted by variation of the ratio of pull-up to pull-down resistances.
22. For equal margin, Vinv is set as ______ of logic voltage swing.
A. equal
B. half of
C. one third
D. twice
Answer: B
Since the logic high level is limited by barrier potential then for equal margins Vinv is set to half of the logic voltage swing.
23. For E-MESFET, Vinv is set in midway between
A. Vdd and Vss
B. Vt and Vin
C. Vt and Vout
D. barrier potential and ground
Answer: D
In a pull-down device that is E-MESFET, the inverter threshold voltage Vinv is set midway between barrier potential and ground.
24. To improve packing density, gate length should be smaller.
A. true
B. false
Answer: B
To improve packing density, the gate length should be larger for the pull-up device. This will reduce drain to source saturation current.
25. The ratio of Zp.u./Zp.d. for E-MESFET is
A. 1/10
B. 10/1
C. 4/1
D. 1/4
Answer: B
For E-MESFET, the Zp.u./Zp.d. ratio is 10/1. For MESFET with Lp.u.=Lp.d., Wp.u./Wp.d. is equal to 1/10.
26. In direct coupled logic, the input transistor base is connected to
A. base output
B. emitter output
C. collector output
D. ground
Answer: C
In directly coupled logic, the input transistor base is directly connected to the collector output without any base resistors.
27. Direct-coupled logic is easy to design.
A. true
B. false
Answer: A
Direct-coupled logic devices have fewer components, are economical, and are simpler to design and fabricate.
28. For cascade inverters, the relation suitable is
A. Vin = Vout > Vinv
B. Vin = Vout = Vinv
C. Vin < Vout > Vinv
D. Vin > Vout = Vinv
Answer: B
For cascade inverters without degradation of levels, the relation suitable and required is Vin = Vout = Vinv.
29. MESFET circuits are formed on _____ layers.
A. two
B. three
C. four
D. five
Answer: A
MESFET circuits are formed effectively on two layers – the green implant layer and the red gate-metal layer.
30. If the gate-metal layer is in contact with the implant layer _____ is formed.
A. diode
B. transistor
C. switch
D. buffer
Answer: B
If the gate-metal layer is in contact with the implant layer a transistor is formed. The implanted layer and the gate-metal layer interact to form the Schottky gate where they cross one another.
