Bharat Electronics Limited (BEL) Question Bank continued from Part 3…
Q-20. State a way to improve SNR at the input of an amplifier.
A : Signal to Noise Ratio (SNR) at the input of an amplifier can be improved by decreasing the source impedance (or resistance).
Q-21. Why are N channel FETs superior to P channel FETs?
A : N channel FETs are superior to P channel FETs because the mobility of electrons are greater than that of holes.
Q-22. What is Diac & Triac? is a solid state device which works as a 2 terminal bidirectional switch
A : Diac is a solid state device that works as a two-terminal bidirectional switch whereas Triac is a three-terminal bidirectional switch.
Q-23. If two amplifiers having same bandwidth are cascaded, what will be the bandwidth of the resulting amplifier?
A : The bandwidth of the resulting amplifier will be greater than that of each stage.
Q-24. Which has the largest bandwidth among RC coupled, Transformer coupled and Direct coupled amplifier?
A : Direct coupled amplifier has the largest bandwidth.
Q-25. A JFET has a potential divider bias arrangement. By mistake the resistor between the gap and the power supply terminal is removed. What will be the effect on the JFET?
A : The JFET will now work as a switch and not as an amplifier.
Q-26. What is the ripple factor of half-wave rectifier?
A : For half-wave rectifier, ripple factor is 1.21.
Q-27. In the high frequency region of an RC coupled amplifier, how will the circuit behave?
A : The circuit will behave as a Low Pass Filter.
Q-28. Where is zener diode used?
A : Zener diode is primarily used for producing constant voltage.
(Continued to Part 5…)