Description : What is the purpose of a frequency-determining network in an rf amplifier?
Last Answer : To provide maximum impedance at the desired frequency.
Description : What is the purpose of the rectifier in a magnetic amplifier?
Last Answer : The rectifier eliminates hysteresis loss.
Description : What is the purpose of the pump in a parametric amplifier?
Last Answer : Supplies the electrical energy required to vary the capacitance.
Description : What is the purpose of the circulator in a tunnel-diode amplifier?
Last Answer : Prevent feedback to the tuned input circuit.
Description : What is the purpose of an amplifier-coupling network?
Last Answer : To transfer energy (a signal) from one stage to another.
Description : When measuring a transmitter’s frequency against a suitable standard, the frequency to be measured is taken from the A. oscillator stage B. intermediate amplifier C. buffer stage D. final RF stage
Last Answer : D. final RF stage
Description : A buffer amplifier is usually associated with (A) High input resistance (B) Low output resistance (C) Unity Voltage Gain (D) All Of the above
Last Answer : A buffer amplifier is usually associated with (A) High input resistance (B) Low output resistance (C) Unity Voltage Gain (D) All Of the above
Description : List the three techniques used by manufacturers to buffer optical fibers.
Last Answer : Tight-buffered, loose-tube, and gel-filled loose-tube.
Description : In addition to a primary coating, manufacturers add a layer of buffer material for what reasons?
Last Answer : To provide additional mechanical protection and preserve the fiber's inherent strength.
Description : Main purpose of buffer stock is : (a) to save food grains from pest attack (b) to stop price fluctuations (c) to meet the crisis of low production (d) both (b) and (c)
Last Answer : (d) both (b) and (c)
Description : If C4 were removed from the circuit, what would happen to the output of the amplifier?
Last Answer : The output would decrease. (C4 decouples R2 preventing degenerative feedback from R2.)
Description : What components form the input-signal-developing impedance for the amplifier?
Last Answer : C2 and the secondary of T1.
Description : What two methods are used to compensate for the problems that cause low gain in an rf amplifier?
Last Answer : . RF transformers are used and the transistor is neutralized.
Description : What problem is caused in an rf amplifier by a loosely coupled transformer?
Last Answer : A too-narrow bandpass.
Description : What is the most common form of coupling for an rf amplifier?
Last Answer : Transformer coupling.
Description : Can a parallel LC circuit be used as the frequency determining network for an rf amplifier?
Last Answer : Yes.
Description : If the output impedance of an amplifier circuit is decreased, what is the effect on the gain?
Last Answer : The gain decreases.
Description : If the input-signal-developing impedance of an amplifier is increased, what is the effect on the gain?
Last Answer : The gain increases.
Description : What component in an amplifier circuit tends to limit the low-frequency response of the amplifier?
Last Answer : The coupling capacitor (C3).
Description : What compone What components What components can be used to increase the high frequency response of an amplifier?
Last Answer : Peaking coils.
Description : What is the major factor that limits the high-frequency response of an amplifier circuits?
Last Answer : The capacitance of the circuit.
Description : What are the factors that limit the frequency response of a transistor amplifier?
Last Answer : The capacitance and inductance of the circuit and the interelectrode capacitance of the transistor.
Description : If current gain is required from an rf amplifier, what type of component should be used as an output coupling element?
Last Answer : A step-down transformer.
Description : What are the upper and lower frequency limits of an amplifier?
Last Answer : The half-power points of a frequency-response curve. The upper and lower limits of the band f frequencies for which the amplifier is most effective.
Description : What is the bandwidth of an amplifier?
Last Answer : The difference between the upper and lower frequency limits of an amplifier.
Description : When is degeneration tolerable in an amplifier?
Last Answer : When it is necessary to prevent amplitude distortion.
Description : In the basic transistor amplifier discussed earlier, what is the relationship between the polarity of the input and output signals?
Last Answer : The signals are opposite in polarity or 180 degrees out of phase with each other.
Description : What amplifier class of operation is the most inefficient but has the least distortion?
Last Answer : Class A.
Description : What two primary items determine the class of operation of an amplifier?
Last Answer : The amount of bias and the amplitude of the input signal
Description : The input and output signals of a JFET amplifier have what phase relationship?
Last Answer : They are 180 degrees out of phase.
Description : What is used to bias a magnetic amplifier so that the control winding remains free to accept control (input) signals?
Last Answer : A bias winding and associated circuitry.
Description : At what portion of the magnetization curve should a magnetic amplifier be operated?
Last Answer : . The knee of the curve.
Description : What is the basic principle of a magnetic amplifier?
Last Answer : change in inductance in a series LR circuit causes a change in true power.
Description : What is the frequency classification of a magnetic amplifier
Last Answer : An audio (or low) frequency power amplifier.
Description : Can a difference amplifier have more than two inputs?
Last Answer : No
Description : What is the difference between a subtractor and a difference amplifier?
Last Answer : . The difference amplifier multiplies the difference between the two inputs by the gain of the circuit while the subtractor merely subtracts one input signal from the other
Description : What is a scaling amplifier?
Last Answer : A summing amplifier that applies a factor to each input signal beforeadding the results.
Description : Can a summing amplifier have more than two inputs?
Last Answer : Yes, a summing amplifier can have as many inputs as desired.
Description : What is the difference between a summing amplifier and an adder circuit?
Last Answer : The adder simply adds the input signals together while the summing amplifier multiplies the sum of the input signals by the gain of circuit.
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 : In the inverting configuration, what is the voltage (for all practical purposes) at the inverting input to the operational amplifier if the input signal is a 1-volt, peak-to-peak sine wave?
Last Answer : 0 volts.
Description : What does the term "closed-loop" mean in the closed-loop configuration of an operational amplifier?
Last Answer : The use of degenerative (negative) feed-back
Description : What are the three requirements for an operational amplifier?
Last Answer : . Very high gain, very high input impedance, very low output
Description : If the single-input, differential-output, differential amplifier has an output signal taken between the two output terminals, what will the peak-to-peak amplitude of this combined output be?
Last Answer : 200 millivolts. A-18. a. Differential amplifier
Description : If the differential amplifier is configured with a single input and differential outputs, what will the output signals be?
Last Answer : Each output will be a sine wave with a peak-to-peak amplitude of 100 millivolts. The output signals will be 180 degrees out of phase with each other.
Description : If the two input signals to a difference amplifier are equal in amplitude but neither in phase nor 180 degrees out of phase, what will the output signal be?
Last Answer : . A different shape than the input signals but larger in amplitude.
Description : If only one input signal is used with a difference amplifier, what will the output signal be?
Last Answer : Equal in shape and frequency to the input signal; larger in amplitude than the input signal; half as large in amplitude as when two input signals were used that were 180 degrees out of phase.
Description : If the two input signals to a difference amplifier are equal in amplitude and 180 degrees out of phase, what will the output signal be?
Last Answer : Equal in shape and frequency to each input signal and larger in amplitude by two times than
Description : . If the two input signals of a difference amplifier are in phase and equal in amplitude, what will the output signal be?
Last Answer : No output (the signals will "cancel out").
Description : What two transistor amplifier configurations are combined in the single-transistor, two-input, single-output difference amplifier?
Last Answer : Common emitter (CE) and common base (CB)