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NAVEDTRA 14180A
Amplifiers ET2 BIBS MAR 2017 EXAM
Question | Answer |
---|---|
Which term describes the size of a signal? | amplitude |
Which type of device enables an input signal to control an output signal? | amplifier |
Which two ways can most amplifiers be classified? | function or frequency response |
What is an amplifier in which the output signal voltage is larger than the input signal voltage? | voltage amplifier |
What is an amplifier in which the output power signal is larger than the input signal power? | power amplifier |
Audio amplifier,, RF amplifier, along with what else are the three broad categories of frequency response for amplifiers? | video amplifier |
An audio amplifier is designed to amplify frequencies between 15 Hz and what? | 20 kHz |
RF amplifiers designed to amplify frequencies between 10 kHz to what? | 100,000 MHz |
A video amplifier is an amplifier designed to amplify a ban of frequencies from 10 Hz and what? | 6 MHz |
How many classes of operation for an amplifier are there? | four |
Which class of amplifier has the characteristics of good fidelity and low efficiency? | class A |
Which term means that the output signal is just like the input in all respects except amplitude? | fidelity |
What is any undesired change in a signal in a signal from input to output? | distortion |
Which operating class is the amplifier if the amplifying device is biased in such a way that current flows in the device for 51%-99% of the input signal? | class AB |
Which type of amplifier has the worst fidelity? | class C |
What is the process known as of transferring energy between circuits? | coupling |
What is the most commonly used coupling in amplifiers? | RC coupling |
What is caused by a small part of the signal from the amplifier output being sent back to the input of the amplifier? | oscillation |
What is the process of sending part of the output signal of an amplifier back to the input of the amplifier called? | feedbackt |
What is accomplished by adding part of the output signal in phase with the input signal? | positive feedback |
What is accomplished by adding part of the output signal out of phase with the input signal? | negative feedback |
Which type of device produces two signals that differ in phase from each other from a single input signal? | phase splitter |
Which type of amplifier uses two transistors whose output signals are added together to provide a larger gain than a single transistor could provide? | push-pull |
What amplifies signals that represent video information? | video amplifier |
Which type of amplifier will most likely be used by any device that uses frequency between 10 kHz and 100,00 MHz? | RF amplifier |
What provided a "picture" of the performance of an amplifier at various frequencies? | frequency-response curves |
What property of an amplifier is the difference between the frequency limits of the amplifier? | bandwidth (BW) |
Any frequency that produces less than what percent of the maximum output voltage (or current) is outside the bandwidth and in most cases, is not considered a useable output of the amplifier? | 70.7% |
Capacitance opposes changes in voltage, which what opposes changes in current? | inductance |
What are inductors (coils) when used for high frequency compensation called? | peaking coils |
What is the use of both series and shunt peaking coils known as? | combination peaking |
Which circuit provides the desired response at a particular frequency? | frequency-determining network |
What is the parallel LC circuit used as a frequency-determining network called? | tuned circuit |
What is the most common method used to couple RF amplifiers? | transformer coupling |
For transformers, what term refers to the amount of energy transferred from the primary to the secondary of the transformer? | coupling |
The losses in a transformer are classifies as copper loss, eddy-current loss, and what else? | hysteresis loss |
What is caused by the realignment of the magnetic domains in the core of the transformer each time the polarity of the magnetic field changes? | hysteresis loss |
Which process solves the problem of interelectrode capacitance in the transistor of an RF amplifier? | neutralization |
Which type of amplifier can have two input signals and/or two output signals? | differential |
Which type of amplifier can add, subtract, multiply, divide, and even perform the calculus operations of integration and differentiation? | operational |
How many outputs can the differential amplifier have? | two |
how many stages are there within the operational amplifier? | three |
Which type of operation does the operational amplifier have without feedback? | open-loop |
What is a point in a circuit which is at ground potential (0v) but is not connected to ground? | virtual ground |
What will always produce an output that is equal to the sum of the input signal but opposite in polarity? | adder circuit |
What property of the circuit is determined by the ratio between the feedback resistor and the input resistors? | gain |
Which circuit multiplies each input by a factor and then adds these values together? | scaling amplifier |
The magnetic amplifier has very high efficiency (up to what percent)? | 90% |
What does the magnetic amplifier use to amplify a signal? | electromagnetism |
What is defined as the measure of the ability of a material to act as a path for additional magnetic lines of force? | permeability |
What is defined as the number of lines of force passing through a given area? | flux density |
What is a magnetic-core reactor (coil) whose reactance is controlled by changing the permeability of the core? | saturable-core reactor |
What is the point of maximum curvature on a magnetization curve? | knee of the curve |
What does a magnetic amplifier have in addition to a saturable-core reactor? | rectifier |