What is a tuned amplifier?
Ans. The tuned amplifier is used for amplifying a signal of specific frequency or narrowband of frequencies is known as a tuned amplifier.
What is fundamental difference between audio amplifiers and tuned amplifiers?
Ans. The Fundamental difference between audio amplifiers and tuned amplifiers is the bandwidth they are expected to amplify.Audio-Frequency spectrum(20Hz-20kHz) equally well throughout while tuned amplifiers amplify a relatively narrow portion of RF spectrum,rejectting all other frequencies.
Give the typical value of Q of a coil used in class C tuned amplifiers.
Ans. 50 or more
What is the typical value of Q for the circuit of a class C tuned amplifier?
Ans. 10 or more.
Why the quality factor of the whole circuit is less than that of the inductor?
Ans. The Quality factor Q for the whole circuit is less than of the inductor because it includes the effect of load resistance as well as the coil resistance.
Tuned class C amplifiers are used for application involving larger RF power. Why?
Ans. Tuned amplifiers operating in class A operation are not suitable for applications involving larger RF power, because of lower efficiency of class A operation, For application involving larger RF power, like for excitation of transmitting antenna, tuned class C Amplifiers are employed because class C operation has a very high efficiency and is capable of delivering more power in comparison to that of class A operation.
Define Stagger tunning
Ans. A much better overall responses can be had by stagger-tunning the individual stages,as illustrated . Stagger tuned amplifiers are usually designed so that the over all responses exhibits maximal flatness around the center frequency fo . It needs a number of tuned circuits operating in union. The overall frequency response together. since the resonant frequency of different tuned circuits are displaced or staggered, they are reffered to as a stagger tuned amplifiers . The main advantages of stagger tuned amplifiers is incresed bandwidth. Its drawback are reduced selectivity are critical tunning of many tanks circuits. They are used in RF amplifiers stage in radio recivers.
Justify the name of stagger tuned amplifiers.
Ans. Since the resonant frequencies of different tuned circuits used in stagger tuned amplifiers are displaced or staggered.they are reffered to as stagger tuned amplifiers.
What is the advantage of stagger tuned amplifier?
Ans. Stagger tunning results in increased bandwidth.
What are the drawback of stagger tuned amplifiers?
Ans. (i) Reduced selectivity
(ii) Tunning of many tank(L-C) circuits precisely at different frequencies is quite cumbersome.
Give the application of stagger tuned amplifiers.
Ans. Stagger tuned amplifiers are used in RF amplifiers stage in radio recivers.
Explain in brief the effect of changing Q of the coil used in tank circuit, on its bandwidth
Ans. In case of series resonance,higher value of Q factor means not only higher voltage magnification,but also a higher selectivity of tunning coil and that is why it is necessary that the coil be of high inductance and low resistance, In fact, Q factor if a series resonant circuit may be defined as the ratio of resonant frequency to bandwidth.
i.e
Ans. The tuned amplifier is used for amplifying a signal of specific frequency or narrowband of frequencies is known as a tuned amplifier.
What is fundamental difference between audio amplifiers and tuned amplifiers?
Ans. The Fundamental difference between audio amplifiers and tuned amplifiers is the bandwidth they are expected to amplify.Audio-Frequency spectrum(20Hz-20kHz) equally well throughout while tuned amplifiers amplify a relatively narrow portion of RF spectrum,rejectting all other frequencies.
Give the typical value of Q of a coil used in class C tuned amplifiers.
Ans. 50 or more
What is the typical value of Q for the circuit of a class C tuned amplifier?
Ans. 10 or more.
Why the quality factor of the whole circuit is less than that of the inductor?
Ans. The Quality factor Q for the whole circuit is less than of the inductor because it includes the effect of load resistance as well as the coil resistance.
Tuned class C amplifiers are used for application involving larger RF power. Why?
Ans. Tuned amplifiers operating in class A operation are not suitable for applications involving larger RF power, because of lower efficiency of class A operation, For application involving larger RF power, like for excitation of transmitting antenna, tuned class C Amplifiers are employed because class C operation has a very high efficiency and is capable of delivering more power in comparison to that of class A operation.
Define Stagger tunning
Ans. A much better overall responses can be had by stagger-tunning the individual stages,as illustrated . Stagger tuned amplifiers are usually designed so that the over all responses exhibits maximal flatness around the center frequency fo . It needs a number of tuned circuits operating in union. The overall frequency response together. since the resonant frequency of different tuned circuits are displaced or staggered, they are reffered to as a stagger tuned amplifiers . The main advantages of stagger tuned amplifiers is incresed bandwidth. Its drawback are reduced selectivity are critical tunning of many tanks circuits. They are used in RF amplifiers stage in radio recivers.
Justify the name of stagger tuned amplifiers.
Ans. Since the resonant frequencies of different tuned circuits used in stagger tuned amplifiers are displaced or staggered.they are reffered to as stagger tuned amplifiers.
What is the advantage of stagger tuned amplifier?
Ans. Stagger tunning results in increased bandwidth.
What are the drawback of stagger tuned amplifiers?
Ans. (i) Reduced selectivity
(ii) Tunning of many tank(L-C) circuits precisely at different frequencies is quite cumbersome.
Give the application of stagger tuned amplifiers.
Ans. Stagger tuned amplifiers are used in RF amplifiers stage in radio recivers.
Explain in brief the effect of changing Q of the coil used in tank circuit, on its bandwidth
Ans. In case of series resonance,higher value of Q factor means not only higher voltage magnification,but also a higher selectivity of tunning coil and that is why it is necessary that the coil be of high inductance and low resistance, In fact, Q factor if a series resonant circuit may be defined as the ratio of resonant frequency to bandwidth.
i.e
0 Comments