Junior Engineer (Electrical / Electronics)

Q51. A Zener diode is normally operated in the:

• A) Saturation region
• B) Reverse breakdown region
• C) Cut-off region
• D) Forward bias region

Q52. The main function of a heat sink used with power transistors is to:

• A) Increase switching speed
• B) Increase current gain
• C) Dissipate heat and prevent thermal runaway
• D) Reduce leakage current

Q53. In a common-emitter BJT amplifier, the output signal is:

• A) 180° out of phase with the input
• B) 90° out of phase with the input
• C) 270° out of phase with the input
• D) In phase with the input

Q54. The pinch-off voltage of a JFET is the gate-source voltage at which:

• A) Drain current becomes essentially zero
• B) Gate current is maximum
• C) Channel resistance is minimum
• D) Drain current becomes maximum

Q55. An operational amplifier used as a comparator produces an output that:

• A) Is linearly proportional to the input difference
• B) Is always zero
• C) Amplifies linearly over the full input range
• D) Switches between saturation levels depending on which input is larger

Q56. In a full-wave bridge rectifier, the number of diodes used is:

• A) 6
• B) 2
• C) 1
• D) 4

Q57. Compared with a half-wave rectifier, the ripple factor of a full-wave rectifier is:

• A) Equal
• B) Zero
• C) Higher
• D) Lower

Q58. MOSFET is preferred over BJT in high-frequency switching applications mainly because it:

• A) Has lower input impedance than a BJT
• B) Dissipates significantly more heat
• C) Is a voltage-controlled device with very low gate current and fast switching
• D) Has higher current gain than a BJT

Q59. In an SCR, the process of turning the device off by reducing the anode current below the holding current is called:

• A) Triggering
• B) Latching
• C) Commutation
• D) Forward breakover

Q60. A Darlington pair transistor configuration is primarily used to achieve:

• A) Precise voltage regulation
• B) High overall current gain
• C) Low input impedance
• D) High output impedance only