If three amplifiers having the same bandwidth are cascaded, the bandwidth of the resulting amplifier will be Worse than that of each stage
Description : Which of the following methods cannot be used to increase the bandwidth for cascaded RF amplifier stages? A) Wave traps in each stage B) Stagger tuning C) A shunt damping resistor across each tuned circuit D) Doubled tuned transformers with tighter coupling
Last Answer : A) Wave traps in each stage
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 : 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 : Negative feedback in amplifiers (1) increases bandwidth and decreases noise (2) decreases bandwidth and decreases noise (3) increases bandwidth and increases noise (4) decreases bandwidth and increases noise
Last Answer : increases bandwidth and decreases noise
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 : 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 : 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 : The IF amplifiers are connected in what amplifier configuration?
Last Answer : Cascade.
Description : The front-end of a television receiver, having a bandwidth of 7Mhz, and operating at a temperature of 27˚C , consists of an amplifier having a gain of 15 followed by a mixer whose gain is 20. The ... equivalent noise resistance for this television receiver. A. 8760 Ω B. 875Ω C. 8.76Ω D. 0.876Ω
Last Answer : B. 875Ω
Description : The noise output of a resistor is amplified by a noiseless amplifier having a gain of 60 and a bandwidth of 20 kHz. A meter connected at the output of the amplifier reads 1mV RMS. If the bandwidth of the amplifier is reduced to ... does the meter read now? A. 0.5 mV B. 0.5 µV C. 5.0 mV D. 5.0 µV
Last Answer : A. 0.5 mV
Description : A low-pass filter with a cut-off frequency of 30 Hz is cascaded with a high pass filter with a cut-off frequency of 20 Hz. The resultant system of filters will function as (A) an all – pass filter (B) an all – stop filter (C) an band stop (band-reject) filter (D) a band – pass filter
Last Answer : A low-pass filter with a cut-off frequency of 30 Hz is cascaded with a high pass filter with a cut-off frequency of 20 Hz. The resultant system of filters will function as a band – pass filter
Description : Define gain and bandwidth of an amplifier.
Last Answer : Bandwidth The range of frequency over which the voltage gain is equal to or greater than 70.7% of its maximum value Gain: The ratio of output parameter (voltage/ current /power) to the input parameter (voltage/ current /power) of an amplifier is known as gain. It is denoted by a letter A
Description : Indicate the false statement. Noise figure is defined as A. the ratio of the S/N power supplied at the input terminal of a receiver or amplifier to the S/N power supplied to the output or ... under test, both working at the same temperature over the same bandwidth and fed from the same source
Last Answer : C. an unwanted form of energy tending to interfere with the proper and easy reception and reproduction of wanted signals
Description : One of the following is a possible cause of an abrupt frequency variation in a self exited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant frequency ... capacitor in the oscillator D. Loose connections in the oscillator, amplifier, or antenna circuits.
Last Answer : D. Loose connections in the oscillator, amplifier, or antenna circuits.
Description : Which of the following is one of the possible causes for a slow drift of frequency in a self exited transmitter oscillator circuits resulting to a poor frequency stability? A. Poor soldered connections ... , or antenna circuits D. DC and RF heating of resistors, causing then to change values.
Last Answer : D. DC and RF heating of resistors, causing then to change values.
Description : Calculate the noise figure of the receiver whose RF amplifier has an input resistance of 1000Ω and an equivalent shot-noise resistance of 2000Ω, a gain of 25 and load resistance of 125 kΩ. Given that the bandwidth is 1. ... to an antenna with an impedance of 75Ω. A. 30.3 B. 3.03 C. 303 D. .303
Last Answer : A. 30.3
Description : What establishes the receiver bandwidth? A. RF amplifier B. Mixer C. Local oscillator D. IF amplifier
Last Answer : D. IF amplifier
Description : The Bandwidth of an RC-coupled amplifier is limited by: A) coupling capacitors at the low frequency end and bypass capacitors at the high frequency end B) coupling capacitors at the high frequency ... at the low frequency end and bypass as well as coupling capacitors at the high frequency end.
Last Answer : C) bypass and coupling capacitors at the low frequency end and shunt capacitors at the high frequency end and
Description : What is the bandwidth of an amplifier?
Last Answer : The difference between the upper and lower frequency limits of an amplifier.
Description : If the unity-gain point of the operational amplifier used in question 24 is 500 kilohertz, what is the bandwidth of the circuit?
Last Answer : 50 kilohertz (Gain = 10; Gain-Bandwidth Product = 500,000) 500,000(Hz)
Description : What is the advantage of designing a limited bandwidth into a servo amplifier?
Last Answer : Unwanted noise-generated frequencies are rejected
Description : The unity gain bandwidth of an inverting amplifier is 10 MHz What would be the bandwidth if the gain is increased to 10 V/V? A) 100 MHz B) 1 MHz C) 10 MHz D) 1 kHz
Last Answer : The unity gain bandwidth of an inverting amplifier is 10 MHz What would be the bandwidth if the gain is increased to 10 V/V? A) 100 MHz B) 1 MHz C) 10 MHz D) 1 kHz
Description : Two non -inverting amplifiers, one having a unity gain and the other having again of twenty are made using identical operational amplifiers. As compared to the unity gain amplifier, the amplifier with gain twenty has
Last Answer : Two non -inverting amplifiers, one having a unity gain and the other having again of twenty are made using identical operational amplifiers. As compared to the unity gain amplifier, the amplifier with gain twenty has less bandwidth
Description : different types of feedback amplifiers
Last Answer : Types of feedback amplifiers: 1. Positive feedback amplifiers 2. Negative feedback amplifiers (i)voltage series feedback amplifiers (ii)voltage shunt feedback amplifiers (iii)current series feedback amplifiers (iv)current shunt feedback amplifiers
Description : Define each of following terms of operational amplifiers i) Slew rate ii) Input offset voltage iii) Voltage gain iv) Input capacitance
Last Answer : i) Slew rate:- Maximum rate of change of o/p voltage per unit of time. It is express in volt/µsec. ii) Input offset voltage:- The voltage that must be applied between two ... capacitance that can be measured at either be inverting or non-inverting terminal with other terminal connected to ground.
Last Answer : If three stage amplifiers has individual stage gain of 10 db, 5 db & 12 db then the total gain 27 db
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 : 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
Description : Due to its construction, the component in figure 'A' shown in the illustration has which of the listed advantages compared to bipolar devices? EL-0078 A. Operates with higher voltages and ... as a controllable rectifier. D. Has very high input resistance and uses practically no gate current.
Last Answer : Answer: D
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
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
Description : List two common usages of magnetic amplifiers
Last Answer : Servosystems, temperature recorders, or power supplies