০২। A 1 ms pulse can be stretched to 1 sec pulse by using
ক) an astable multivibrator
খ) a monostable multivibrator
গ) a bistable multivibrator
ঘ) a Schmitt trigger circuit
০৩। A 12 kHz pulse wave-form is amplified by a circuit having an Upper cut-off frequency of 1 MHz. The minimum input pulse width that can be accurately reproduced is
ক) 83.33 μ sec
খ) 1 μ sec
গ) 0.1 m sec
ঘ) 3.5 m sec
০৪। A 120 V, 30 Hz source feeds a half wave rectifier circuit through a 4 : 1 step down transformer, the average output voltage is
ক) 30 V
খ) 13.5 V
গ) 10 V
ঘ) 7.07 V
০৫। A 741 type op-amp has a gain bandwidth product of 1 MHz. A non-inverting amplifier using this op-amp and having a voltage gain of 20 dB will exhibit a -3dB bandwidth of
ক) 50 kHz
খ) 100 kHz
গ)
ঘ)
০৬। A bipolar transistor is a __________ controlled devices whereas a FET is a __________ controlled devices.
ক) current, voltage
খ) current, current
গ) voltage, current
ঘ) voltage, voltage
০৭। A BJT amplifier has a power gain of 0.5 from source to base. The power gain in dB is
ক) -0.3 dB
খ) -3 dB
গ) -6 dB
ঘ) -10 dB
০৮। A BJT is said to be operating in saturation region if
ক) both junctions are reverse biased
খ) both junctions are forward biased
গ) base emitter junction is forward biased and base collector junction is reverse biased
ঘ) base collector junction is forward biased and base emitter junction is reverse biased
০৯। A boot strap generally incorporates
ক) CB configuration
খ) CE configuration
গ) emitter follower
ঘ) none of the above
১০। A bridge diode circuit using ideal diodes has in input voltage of 20 sin ωt volts. The average and rms values of output voltage are
ক)
খ)
গ)
ঘ)
১১। A bridge rectifier circuit has a dc load current of 10 mA and a filter capacitance of 1000 μF. The peak to peak ripple voltage is
ক) 0.01 V
খ) 0.05 V
গ) 0.1 V
ঘ) 0.5 V
১২। A bridge rectifier circuit has input of 50 Hz frequency. The load resistance is RL and filter capacitance is C. For good output wave shape, the time constant RLC should be at least equal to
ক) 10 ms
খ) 20 ms
গ) 50 ms
ঘ) 100 ms
১৩। A buffer amplifier should have
ক) high output impedance and high input impedance
খ) high output impedance and low input impedance
গ) low output impedance an low input impedance
ঘ) low output impedance and high input impedance
১৪। A buffer amplifier should have
ক) high input impedance and low output impedance
খ) high input impedance and high output impedance
গ) low input impedance and high output impedance
ঘ) low input impedance and low output impedance
১৫। A bypass capacitor produces
ক) dc ground
খ) ac ground
গ) both dc and ac ground
ঘ) none of the above
১৬। A capacitor input filter relies on
ক) average detection
খ) peak detection
গ) both (a) and (b)
ঘ) neither (a) nor (b)
১৭। A cascade amplifier stage is equivalent to
ক) common emitter stage followed by a common base stage
খ) common base stage followed by an emitter follower
গ) an emitter follower stage followed by a common base stage
ঘ) a common base stage followed by a common emitter stage
১৮। A cascade amplifier will have higher cut off frequency
ক) equal to that of single stage amplifier
খ) less than that of single stage amplifier
গ) more than that of single stage amplifier
ঘ) none of these
১৯। A CB amplifier has a = 0.98 and RL = 600 Ω. If IE = 3.5 mA, the current gain is