State classification of Amplifiers.

1 Answer

Answer :

CLASSIFICATION OF AMPLIFIERS:

A] Based on input signal

1. Small signal amplifiers

2. Large signal amplifiers

B] Based on output signal

1. Voltage amplifier

2. Power amplifier

C] Based on biasing conditions

1. Class A amplifier

2. Class B amplifier

3. Class AB amplifier

4. Class C amplifier

D] Based on frequency response

1. Audio frequency amplifier

2. Radio frequency amplifier

E] Based on coupling

1. Direct coupled amplifiers

2. R-C Coupled amplifier

3. Transformer coupled amplifier

Related questions

Description : Compare Class A ,Class B, Class C and class AB power amplifiers on the basis of: i)Angle of conduction ii)Efficiency iii)Position of operating pointing power dissipation iv)Distortion

Last Answer : Compare Class A ,Class B, Class C and class AB power amplifiers on the basis of: i)Angle of conduction ii)Efficiency iii)Position of operating pointing power dissipation iv)Distortion

Description : Comment on the effect of negative feedback on the gain, input and output resistance of the feedback amplifiers.Describe the gain bandwidth product term used in this context and its importance.

Last Answer : Effect of negative feedback: 1. Gain decreases with negative feedback. 2. Input resistance increases with negative feedback. 3. Output resistance decreases with negative feedback. Explanation ... feedback bandwidth increases which means it is stable output on more range of frequency.

Description : Classify the power amplifiers on the basis of operation and input/output waveforms.

Last Answer : Depending upon the operation and input/output waveforms power amplifiers are classified into following type. 1) Class A amplifier. 2) Class B amplifier. 3) Class C amplifier. 4) Class AB amplifier. 5) Class D amplifier

Description : Explain the term crossover distortion. State methods to overcome it.

Last Answer : Explanation:-  * Cross over distortion occurs in Class B push pull Amplifier.  * In the push-pull configuration, the two identical transistors get into conduction, one after the other and the output ... transistors won t be OFF at the same time. The remedy is to use Class AB amplifier.

Description : Sketch circuit diagram of common source FET Amplifier. State working principle of it.

Last Answer : Working: -  * When small a.c. signal is applied to the gate, it produces variation in the gate to source voltage. This produces variation in the drain current. As the gate to source ... and we get amplification. Thus the AC output voltage VDS is 180º out of phase with AC input voltage.

Description : State the need of tuned amplifier in electronic circuits.

Last Answer : Necessity of tuned amplifier: 1. Selection of the desired radio frequency signal. 2. Amplification of the selected signal to a selected voltage level.

Description : State advantages of negative feedback used in feedback amplifier.

Last Answer : Advantage of negative feedback amplifier: * Increased stability in gain * Increased bandwidth * Less amplitude and harmonic distortion * Decreased noise * Less frequency distortion * Less non-linear distortion * Input and output resistance can be modified as desired

Description : Draw the circuit of complementary, symmetry push pull amplifier and explain its working.

Last Answer : COMPLEMENTRY SYMMETRY CLASS B PUSH PULL AMPLIFIER  Circuit Diagram:  Circuit description: * Two transistors one NPN & other PNP is used in the circuit so they are complementary to each other. ... conducts & NPN remains OFF.  So we get remaining half cycle in the output.

Description : Explain stagger tuned amplifier with the help of waveforms.

Last Answer : Circuit Diagram: Above figure shows two-stage tuned voltage amplifier. The stagger tuning in this circuit, may be achieved by resonating the tuned circuits L1C1 and L2C2 to slightly different ... outside the pass-band. Because of the stagger tuning there is a loss of voltage gain.

Description : Explain with circuit diagram and waveform the operation of class AB push pull power amplifier.

Last Answer : Class AB Push Pull Power Amplifier:  Circuit Diagram:  Circuit Decription: The circuit consists of two centre-tapped transformers T1 and T2, two identical transistors Q1 and Q2 , Resistor R and ... two halves & produces a full sine wave in the load resistor. Waveform :

Description : Define the term related to power amplifier. (i) Efficiency (ii) Voltage gain

Last Answer : (i) Efficiency: Efficiency of the power amplifier is defined as the ratio of maximum a.c. output power to the d.c. input power. Mathematically (ii) Voltage gain: Voltage gain of the power amplifier is defined as the ratio of output voltage to the input voltage. Mathematically,

Description : Draw Bootstrap sweep generator circuit. Compare Miller Integrator and bootstrap sweep generator with respect to the technique used.

Last Answer : Circuit diagram of bootstrap sweep generator: Miller Integrator Bootstrap sweep generator It is an integrator used to convert input step waveform into ramp waveform. In ... than Bootstrap sweep circuit The linearity of sweep voltage is poor than Miller integrator

Description : Explain principle of feedback amplifier.

Last Answer : Block diagram of feedback amplifier:- Explanation:- * Feedback is a process of injecting some energy from the output and then it back to the input. The amplifier which use the feedback principle are ... Now, The quantity β = Vf /Vo is called as feedback ratio or feedback fraction.

Description : Define : (i) Sweep time (ii) Retrace time

Last Answer : (i) Sweep time: It is defined as time interval taken by time based signal generator to increase from minimum to maximum voltage. (ii) Retrace time: It is defined as time taken by time based signal generator to decrease from maximum to minimum voltage.

Description : Describe the operation of double tuned amplifier with the help of neat circuit diagram and mention its applications.

Last Answer : Circuit diagram: Operation:  *The signal to be amplified is applied at the input terminal through the coupling capacitor CC  *The resonant frequency of the tuned circuit L1 C1 is made equal ... : (i) Radio and T .V broadcasting as tuning circuit. (ii) Wireless communication system.

Description : Compare the fixed voltage regulators using 78XX and 79XX.

Last Answer : Compare the fixed voltage regulators using 78XX and 79XX.

Description : Compare between RC phase shift oscillator and crystal oscillator.

Last Answer : RC phase shift oscillator Crystal oscillator This oscillator is used for low frequency range. Quartz crystal is mainly used in radio-frequency (RF) oscillators Used resistor and capacitor ... RC network is used as feedback network. Crystal is connected in feedback.

Description : With the help of neat circuit diagram, explain the operation of voltage shunt type feedback amplifier.

Last Answer : Diagram:  Fig. shows common emitter transistor amplifier with a feedback resistor RF connected between its output and input terminals. This is collector to base biasing when the input signal is ... As IS = If + Ii it is shunt type therefore it voltage shunt negative feedback amplifier.

Description : Draw the circuit diagram of class AB power amplifier and describe its working.

Last Answer : Circuit diagram: Circuit Description: The circuit consists of two center-tapped transformers T1 and T2, two identical transistors Q1 and Q2 , Resistor R and diode D. The DC voltage ... and Q2 conduct, as soon as input cross zero, negative sinusoidal voltage will appear across load.

Description : Justify the need of current time base generator to obtain the specified sawtooth waveform with one example.

Last Answer : Justification:- * Current Time base generator is a circuit where the output current is a linear function of time over a specified time interval. * Time base circuits are used by radar systems to determine ... the time. * The diode D does not conduct during the sweep, because it is reverse biased.

Description : Describe the operation of class-C type of power amplifier with the help of neat sketch.

Last Answer : Circuit diagram: Operation: * Class C power amplifier is a type of amplifier where the transistor conducts for less than one half cycle of the input signal. Less than one ... resonant circuit oscillates in one frequency (generally the carrier frequency) all other frequencies are attenuated. 

Description : Compare small signal amplifier with power amplifier

Last Answer : Parameters Small signal Amplifiers Power Amplifiers Amplification quantity It increases voltage into high resistance load. Hence small signal amplifiers are also called as voltage amplifiers. It ... Coupling R-C coupling Transformer coupling Power output low High

Description : List the types of coupling used in BJT amplifier. 

Last Answer : Types of coupling used in BJT amplifier: i. Resistance capacitance (RC)coupling ii. Impedance coupling iii. Transformer coupling iv. Direct coupling

Description : Is it possible to bridge an odd number of amplifiers?

Last Answer : No. That's not possible. Amplifiers can only be bridged in pairs, and pairs of pairs, etc. And if they're not identical amps, you're asking for trouble, too. Some stereo amplifiers are wired so that you ... 4-channel, and he's bridging them in some odd way to create a balanced pair of pair of amps.

Description : What are antenna amplifiers used for?

Last Answer : Antenna amplifiers are used to strengthen the signal being supplied to an appliance such as your TV. Amplifiers are necessary when the signal is weak and interferes with your TV reception.

Description : Can I get government assistance if I am deaf and need phone amplifiers?

Last Answer : Some states do have assistance available-- Nevada and Nebraska are two examples. Help from the Federal Government directly is not available through Medicare or the National Institute on Deafness and Other ... do have a directory of local groups that will help-- www.nidcd.nih.gov/directory/

Description : Are phone amplifiers bad for your hearing?

Last Answer : They can be bad for your hearing if they are putting out more than 105 dB. 10 minutes of noise at 105 dB can damage your hearing. Though minor damage can be repaired by itself, repeatedly getting minor damage adds up to major damage and hearing loss.

Description : Are car amplifiers just about volume, or do they improve sound quality, as well?

Last Answer : Cap amplifiers can provide an enhanced audio experience as they often are able to reproduce a wider range of audio frequencies compared to many stock car stereos.

Description : Does the volume go to "11" on any car amplifiers?

Last Answer : No. Police can pull you over for noise pollution so they tend not to make them do higher.

Description : Which car amplifiers work best with MP3 files?

Last Answer : Pioneer is the best amplifer and car system that works with MP3 files.

Description : Are the amplifiers easy to remove?

Last Answer : Yes it's easy to remove amplifiers from your car. First make sure the fuse is out of the power wire , so the wire is not live. Then disconnect the wires from your amp. Then unscrew the amp from where it's mounted.

Description : Are there special amplifiers for hybrid and electric vehicles?

Last Answer : Yes, they draw power differently as to not kill the engine.

Description : Negative feedback in amplifiers – (1) increases bandwidth and decreases noise (2) decreases bandwidth and decreases noise (3) increases bandwidth and in-creases noise (4) decreases bandwidth and increases noise

Last Answer : (1) increases bandwidth and decreases noise Explanation: Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or ... be controlled. This can be conveniently achieved by employing a technique, called the feedback.

Description : Negative feedback in amplifiers – (1) increases bandwidth and decreases noise (2) decreases bandwidth and decreases noise (3) increases bandwidth and in-creases noise (4) decreases bandwidth and increases noise

Last Answer : (1) increases bandwidth and decreases noise Explanation: Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or ... be controlled. This can be conveniently achieved by employing a technique, called the feedback.

Description : Common basic applications for the operational amplifier include ____________. A. counting, pulsing and clocking amplifiers B. summing, scaling and difference amplifiers C. step-up, step-down and rectifying amplifiers D. all of the above

Last Answer : Answer: B

Description : Operational amplifiers, used primarily in analog circuits, are characterized by ____________. A. high input impedance, high gain and low output impedance B. high input impedance, high gain and high output ... gain and high output impedance D. low input impedance, high gain and low output impedance

Last Answer : Answer: A

Description : The conversion of the throttle command voltage to the signal necessary to achieve the desired shaft RPM is accomplished by the _____________. A. ahead or astern function generator of the ... circuit C. operational amplifiers in the autorotation circuit D. long time constant amplifier circuit

Last Answer : Answer: A

Description : Since the characteristics of the device shown in figure 'A' of the illustration includes a stable voltage and low current while operating, it can be suitably used in _____________. EL-0065 A. oscillators ... . class A and B amplifiers C. generator rectifier and filtering supplies D. all of the above

Last Answer : Answer: A

Description : Indicate the false statement. A. HF mixer are generally noisier than HF amplifiers. B. Impulse noise voltage is dependent on bandwidth C. Thermal noise is independent of the frequency at which is measured. D. Industrial noise is usually of the impulse type.

Last Answer : B. Impulse noise voltage is dependent on bandwidth

Description : Why are frequency modulation transmitters more efficient? A. Because their power is increased by class C amplifiers B. Because their power is increased by class A amplifiers C. Because their power is increased by class B amplifiers D. Because their power is increased by class AB amplifiers

Last Answer : A. Because their power is increased by class C amplifiers

Description : In a triple conversion superheterodyne receiver, diode mixer stages are operated A. In the linear region B. In the nonlinear region C. As class A amplifiers D. As class B amplifiers

Last Answer : B. In the nonlinear region

Description : If you have available number of power amplifiers with a gain of 100 each, how many such amplifiers do you need to cascade to give an overall gain of 60 dB? A. 3 B. 4 C. 5 D. 2

Last Answer : A. 3

Description : What are feed back amplifiers?

Last Answer : Amplifiers which uses feed back principle is called as feed back amplifiers.

Description : How are amplifiers classified according to the transistor configuration?

Last Answer : 1. Common emitter amplifier 2. Common base amplifier 3. Common collector amplifier

Description : How are amplifiers classified according to the input?

Last Answer : 1. Small – signal amplifier 2. Large – signal amplifier

Description : List the applications of Log amplifiers:

Last Answer : 1.Analog computation may require functions such as lnx, log x, sin hx etc. These functions can be performed by log amplifiers 2.Log amplifier can perform direct dB display on digital voltmeter and spectrum analyzer 3.Log amplifier can be used to compress the dynamic range of a signal

Description : ………………... are needed to communicate with systems on other networks. A. repeaters B. amplifiers C. Bridge D. Gateways

Last Answer : D. Gateways

Description : Which of the following contributes to harmonics distortion in amplifiers? A) Positive feedback B) Presence of noise C) Defective active device D) Non linearity in active device.

Last Answer : D) Non linearity in active device.

Description : What is the primary difference between the NPN and PNP amplifiers?

Last Answer : The polarity of the source voltage