Monday, December 21, 2015

Circuit Design test answers of 2016.

Find Complete and recently updated Correct Question and answers of Circuit Design of Upwork. All Answers updated regularly with new questions. Upwork Circuit Design test answers of 2016.



Question:* The numerical values of what circuit elements are typically represented using colored stripes?

Answer: • resistors

Question:* True or False: A multiplexer has multiple outputs.

Answer: • False

Question:* True or False? Any phase delay between two analog signals is lost after both signals have been three-level Nyquist sampled.

Answer: • False

Question:* Which of these statements expresses De Morgan's theorem?

Answer: • NOT (A AND B) = (NOT A) OR (NOT B)

Question:* In a low-pass filter consisting of a resistor and a capacitor, how will the cut-off frequency change if the capacitance is increased?

Answer: • The cut-off frequency is lower for larger capacitances.

Question:* In a high-pass filter consisting of a resistor and a capacitor, how will the cut-off frequency change if the capacitance is increased?

Answer: • The cut-off frequency is lower for larger capacitances.

Question:* What is the term to describe a multivibrator circuit with two outputs, both of which are stable in time?

Answer: • bistable

Question:* Which of these is an active electronic component?

Answer: • LED

Question:* A high-voltage primary circuit is isolated with the use of an optocoupler on a secondary circuit. Does the addition of the optocoupler add inductance to either circuit?

Answer: • no, the optocoupler does not add inductance

Question:* Consider a switch on a high-voltage circuit that is unsafe to operate manually. How might the switch be safely actuated?

Answer: • by using a secondary, low-voltage relay circuit

Question:* To what does the "sample rate" of a signal refer?

Answer: • how often in time the signal is sampled

Question:* Which of these variable resistors is non-ohmic?

Answer: • varistor

Question:* Which model is generally used for transmission lines?

Answer: • distributed element model

Question:* Consider an npn and a pnp transistor connected in series between the positive and negative terminals of a voltage supply. A signal is input to the base of each and output to ground from their collector-emitter connection. What is the common name for this configuration?

Answer: • a push-pull follower

Question:* Which of these is used as a construction base for prototyping of a circuit?

Answer: • breadboard

Question:* Which of these is NOT an electromechanical component?

Answer: • photodiode

Question:* A "Schmitt trigger" is a simple circuit that employs what distinctive element?

Answer: • an operational amplifier

Question:* How does the breakdown voltage of a dielectric depend upon its thickness?

Answer: • a thick layer of dielectric has a higher breakdown voltage than a thinner layer of the same dielectric

Question:* Which logic operation yield a high output for two high inputs?

Answer: • AND

Question:* An audio tuning circuit is an application of a:

Answer: • band pass filter

Question:* If in a circuit the input voltage (Vin) is applied across the series impedances Z1 and Z2 and the output is taken across Z2, what is the output voltage (Vout) given by?

Answer: • [Z2 / (Z1 + Z2)] . Vin

Question:* True or False? Differential signalling can be employed in both analog circuits and digital circuits.

Answer: • True

Question:* On an alternating-current appliance with a three-prong plug, on which lead should the power switch be connected?

Answer: • the hot lead

Question:* Which of these is NOT a part of a regular DC power supply?

Answer: • differentiator

Question:* Which of the following is a nonlinear circuit element?

Answer: • transistor

Question:* True or False: Reactance is the opposition of a circuit element to a change of electric current or voltage.

Answer: • True

Question:* Of what safety device is this a description: A magnetic or thermal stage that engages an opening of the circuit above a critical value of current?

Answer: • a circuit breaker

Question:* Three-phase alternating-current power is typically distributed on how many independent conductors?

Answer: • three

Question:* Which of these is NOT a method used for electric circuit analysis?

Answer: • Planar Method

Question:* If A = 1 and B = 1 then A XOR B =

Answer: • 0

Question:* Which of the following circuit elements is NOT likely to be found in a 120 VAC to 12 VDC adapter?

Answer: • balun

Question:* True or False? Lightbulb power ratings are only correct for the rated voltage.

Answer: • True

Question:* Which of these can function as an electromagnet?

Answer: • solenoid

Question:* A string of decorative holiday lights is lit except for two burnt-out bulbs. Are the bulbs of the string wired in parallel or series with each other?

Answer: • The lights must be wired in parallel with each other.

Question:* How many diodes are required to build the bridge in a full-wave rectifier that does not employ a transformer?

Answer: • four

Question:* According to Kirchoff's voltage law, the sum of the EMFs in any closed loop is equal to:

Answer: • the sum of the potential drops in that loop

Question:* Which of the following devices can replace a fuse in a circuit and perform the same safety function?

Answer: • a circuit breaker

Question:* True or False: An op-amp configured as an inverting integrator can function as a low pass filter.

Answer: • True

Question:* What are the names of the three terminals on a BJT transistor?

Answer: • base, collector, emitter

Question:* In an 8-bit encoding, how many different values can be represented?

Answer: • 256

Question:* What kind of relationship is described for impedences Z1 through Zn in a circuit, by the following equation? Z(eq) = Z1 + Z2 + … + Zn

Answer: • series

Question:* A resistor is an element that obstructs the flow of current in a circuit in accordance with

Answer: • Ohm's Law

Question:* Which of these is a passive electronic component?

Answer: • capacitor

Question:* Which of these is generally used to measure electrical resistance?

Answer: • Wheatstone Bridge

Question:* In which of the following configurations do the capacitor(s) have the smallest individual voltages?

Answer: • two 100-nF capacitors connected in series to 10 V

Question:* What is the name for the configuration in which an operational amplifier (op-amp) has its output connected to the non-inverting input?

Answer: • positive feedback

Question:* A type of logic gate with outputs high, low, and high impedance is called:

Answer: • tri-state buffer

Question:* True or False? A Fourier-transform spectrometer is suscueptible to Gibbs ringing.

Answer: • True

Question:* What standard circuit network often manifests as a "trim" potentiometer?

Answer: • a voltage divider

Question:* Which of the following is a primary disadvantage of a vacuum-tube amplifier compared with a solid-state amplifier?

Answer: • high heater current

Question:* The typical schematic representation of a transistor carries what one-letter abbreviation?

Answer: • Q

Question:* What do you call a theoretical circuit used in analysis, that retains all of the electrical characteristics of a given circuit?

Answer: • equivalent circuit

Question:* A kilowatt-hour is a typical unit for what quantity?

Answer: • energy

Question:* Which of the following is a primary disadvantage of a solid-state amplifier compared with a vacuum-tube amplifier?

Answer: • poor tolerance for high -current and -voltage transients

Question:* How is the Nyquist rate for a signal related to the bandwidth of the signal?

Answer: • a wider bandwidth requires a higher Nyquist rate

Question:* One 120-VAC circuit has two 60-W light bulbs in parallel and another 120-VAC circuit has a single 100-W bulb. In which circuit is more power dissipated?

Answer: • the two 60-W parallel bulbs

Question:* Which of these inductors exhibits more energy losses at higher frequencies?

Answer: • ferromagnetic core inductor

Question:* A JK flip-flop circuit can be assembled entirely from four of which type of digital gate?

Answer: • NAND

Question:* True or False? XOR and XNOR are both associative.

Answer: • True

Question:* What is the approximate impedance of a universal serial bus (USB) computer connection?

Answer: • 50 Ohm

Question:* What standard logic operation is represented by a household "three-way switch" in which two different switches operate the same light fixture?

Answer: • XOR

Question:* What kind of feedback does a thermostat employ?

Answer: • negative

Question:* In which equivalent circuit can you replace a linear two-terminal circuit by a current source and a parallel impedance?

Answer: • Norton equivalent

Question:* An electrical circuit that converts AC electrical power from a lower voltage to a higher DC voltage is called a:

Answer: • voltage multiplier

Question:* Which of these uses high frequency transformers?

Answer: • switched mode power supply

Question:* What is the function of a diode clamp?

Answer: • to maintain the voltage of a signal between fixed bounds

Question:* To what do the "rails" of an operational amplifier refer?

Answer: • the potentials of the positive and negative terminals of the power supply

Question:* Which of the following statements about phase-locked loops is NOT true?

Answer: • they are digital, not analog devices

Question:* What artifact results from a failure to low-pass filter a signal before analog-to-digital conversion?

Answer: • aliasing

Question:* In a series RLC circuit, a larger series resistance will result in a

Answer: • lower Q factor

Question:* The time between the change in a gate's input to the corresponding change in its output is called:

Answer: • propogation delay

Question:* How many diodes are required to a half-wave rectifier?

Answer: • one

Question:* What is the term to describe a multivibrator circuit with two outputs, one of which is stable in time?

Answer: • monostable

Question:* The number of gate inputs that can be driven by a particular logic gate's output is called that gate's:

Answer: • fanout limit

Question:* What does a Colpitts Oscillator use to produce an oscillating frequency?

Answer: • inductors and capacitors

Question:* What is the name for the process of splitting a signal, inverting one of the two resulting signals, transmitting both signals, inverting one of the signals upon reception of both, then summing the two signals?

Answer: • differential signalling

Question:* In a differentiator circuit, the output is approximately:

Answer: • directly proportional to the rate of change of input

Question:* How many diodes are in the bridge of a three-phase rectifier?

Answer: • six

Question:* What is the term to describe a multivibrator circuit with two outputs, neither of which is stable in time?

Answer: • astable

Question:* Which power supply takes its power from more than one source?

Answer: • UPS

Question:* Which of the following is a linear circuit element?

Answer: • inductor

Question:* One 50-Ohm resistor and two parallel 100-Ohm resistors have the same impedance. In which system do the resistors have lower current when dissipating 1 kW?

Answer: • the system with two 100-Ohm resistors

Question:* On a printed circuit board that supports several different inductors in different circuits, are there any constraints to the layout of the inductors?

Answer: • Yes, the inductors must be oriented at right angles in order to avoid coupling.

Question:* Which kind of filter is produced by placing an input voltage across the series combination of a capacitor and a resistor and using the voltage across the resistor as an output?

Answer: • high-pass

Question:* The minimum root-mean-square magnitude of alternating currents that are likely to cause uncontrollable muscle contraction and heart fibrillation in a human are in what range?

Answer: • 10 to 30 mA

Question:* A milliAmpere-hour is a typical unit for what quantity?

Answer: • charge

Question:* Consider a push-pull follower amplifier: an npn and a pnp transistor connected in series between the positive and negative terminals of a voltage supply to which signal is input to the base of each and output to ground from their collector-emitter connection. In which class is such an amplifier?

Answer: • B

Question:* A group of branches in a circuit forming a complete loop is called a

Answer: • mesh

Question:* How many diodes are required to build a full-wave rectifier that employs a center-tapped transformer?

Answer: • two

Question:* True or False? The presence of the ground lead on a three-prong alternating-current appliance plug alleviates the need for a ground-fault interruptor.

Answer: • False

Question:* On a printed circuit board, what is a flux capacitor?

Answer: • an exploitation of the capacitance that is due to the lateral electric flux between two adjacent printed conductors

Question:* What is the chacteristic feature of heterodyne processing compared with homodyne processing?

Answer: • only heterodyne processing employs frequency conversion

Question:* For which values of inputs A and B would a NAND gate and an XOR gate NOT have the same output?

Answer: • A=0, B=0

Question:* Which of the following combinations of gates could be used to realize the XOR function?

Answer: • one AND, one NAND, and one OR

Question:* Consider a typical household AC circuit that is protected by both a circuit breaker and a ground-fault interruptor. A person accidentally shorts the hot lead to ground, drawing a lethal current of 100 mA. Which of the two safety devices will trip?

Answer: • Only the ground-fault interruptor will trip.

Question:* Of what safety device is this a description: A primary circuit that is magnetically coupled to a secondary circuit in which imbalance of hot and neutral current is measured?

Answer: • a ground-fault interruptor

Question:* For inputs A = 1 and B = 1, which of these logic operations between A and B will yield output 1?

Answer: • XNOR

Question:* Two cross-coupled (the output of one gate serves as one of the other gate's inputs) NOR gates constitutes what type of digital circuit?

Answer: • an SR latch

Question:* The self-induced back voltage in a circuit that occurs when an inductive DC circuit is opened may be safely routed away from the switch with a diode connected across the inductor and against the DC voltage. What is the main disadvantage of this practice?

Answer: • the decay of the current in the inductor is relatively slow

Question:* What is the typical low-voltage cutoff for a "high" signal in transistor-transistor logic (TTL)?

Answer: • 2.4 V

Question:* Why does an "L pad" impedance-matching network bear that name?

Answer: • Because the two resistors in the network are traditionally oriented in the shape of the capital letter "L" on schematic drawings.

Question:* To which of the inputs will the feedback be routed for an operational amplifier (op-amp) employed as a non-inverting amplifier?

Answer: • the inverting input

Question:* Of the following four types of digital latches, which one can be configured (with cross-couplings) to operate as the other three?

Answer: • a JK flip-flop can operate as a set-reset latch, a data flip-flop, and a toggle flip-flop

Question:* A "bias tee" consists of a single output that is capacitively coupled to a radiofrequency signal and inductively coupled to a DC signal. What is the primary purpose of this device?

Answer: • to add a DC offset to an RF signal

Question:* Which model makes the simplifying assumption that all components in a circuit are ideal and all wires conduct perfectly?

Answer: • lumped element model

Question:* In a high-pass filter consisting of a resistor and an inductor, how will the cut-off frequency change if the inductance is increased?

Answer: • The cut-off frequency is lower for larger inductances.

Question:* True or False: The lumped element model is used whenever the circuit's length is greater than the circuit's operating wavelength.

Answer: • False

Question:* In a system with a transmission multiplexer and a reception demultiplexer, how many outputs is it typical for the multiplxer to possess?

Answer: • 1

Question:* A high-voltage primary circuit is isolated with the use of a relay switch on a secondary circuit. Does the addition of the relay circuit add inductance to either circuit?

Answer: • yes, to the secondary circuit

Question:* Dithering of an audiofrequency signal typically occurs at what stage?

Answer: • following digital-to-analog conversion and prior to playback

Question:* Dithering of a digital signal is a common method for combating what underisable phenomenon?

Answer: • edge ringing

Question:* What is the term for the amount by which a signal exceeds the minimum amount for a circuit's proper operation?

Answer: • noise margin

Question:* A transformer in which the windings are surrounded by the core is called

Answer: • shell form

Question:* What is Wein Bridge used for?

Answer: • measurement of capacitance

Question:* True or False? The neutral lead of a polarized alternating-current plug is suitable for use as a chassis ground.

Answer: • False

Question:* True or False? Race conditions can only occur in digital circuits.

Answer: • False

Question:* Which of the following statements can be made concerning A XNOR (B XNOR C) = (A XNOR B) XNOR C ?

Answer: • this is true because XNOR is associative

Question:* In the coil stage prior to rectification, an automobile alternator typically generates which type of electricity?

Answer: • three-phase alternating current

Question:* Which of these is the equivalent of a farad, the unit of capacitance?

Answer: • second/ohm

Question:* Digital latches may be constructed by cross-coupling (the output of one gate serves as one of the other gate's inputs) two of the same gates. What configuration is equivalent to an SR NOR latch for which the two inputs act as Set and Reset?

Answer: • a NOT-S, NOT-R NAND latch

Question:* A differential amplifier made to produce two outputs of equal amplitude but opposite polarity is called

Answer: • phase splitter

Question:* In a low-noise block downconverter (LNB), at what frequency is the amplification typically executed?

Answer: • at the sky frequency



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