Deck 2: Solidstate Devices in Industrial Applications, Operational Amplifiers and Linear ICS

Question 1

Semiconductors are manufactured using a combination of silicon and germanium crystals.

Answer 1

False

Question 2

The term "load"
as applied to power supplies is defined as any device that draws current.

Answer 2

True

Question 3

In a simple half -wave rectifier circuit, a diode is installed in series with the AC input signal and is forward -biased and reversed -biased every half cycle of the AC signal.

Answer 3

False

Question 4

When reversed biased, the light emitting diode behaves like any other diode.

Question 5

The term I_CO is typically expressed in the milliampere range.

Question 6

The saturation voltage of the transistor is slightly higher than zero volts due to variations in the base -emitter voltage and the collector -base voltage.

Question 7

For a transistor operating in the active region, it's not quite in saturation, and its collector current is equal to the base current times the gain.

Question 8

For both PNP and NPN transistors, moving the base voltage toward the collector voltage supply turns the transistor on.

Question 9

Delay time is the most critical parameter when selecting a transistor to switch out of saturation at a high speed.

Question 10

When choosing transistors to design a darlington configuration for a gain of 1000, the sum of the gains of transistors must be greater than or equal to 1000.

Question 11

The characteristic curves of a bipolar junction transistor depict a series of collector currents for a range of collector -emitter voltages.

Question 12

If the transistor in a two resistor bias circuit was substituted with a transistor having a lower gain, the bias point would move to a higher base current curve.

Question 13

Common emitter means that the emitter of the transistor is connected either directly or through a resistor to a voltage that is typically ground but can be negative.

Question 14

In a shunt regulator the transistor is in series with the load.

Question 15

Push -pull converters use more than one switch as opposed to the buck -boost converter, which uses one switch.

Question 16

An inverter is a circuit that accepts an AC voltage and produces a DC voltage.

Question 17

Linear power supplies have become more popular than switching power supplies because they are more efficient.

Question 18

The boost converter has a higher efficiency than the buck converter.

Question 19

Thyristors include all solid state devices that exhibit on -off behavior as opposed to allowing a gradual change in conduction.

Question 20

Both the BJT and the FET are three terminal devices where the current flows through two terminals and is controlled by the third.

Question 21

In a JFET that is reversed biased, the depletion region around the PN junction gets smaller.

Question 22

When the pinch off voltage is applied to the gate of a JFET, the depletion region becomes large enough that conduction of current through the device stops.

Question 23

A CMOS circuit has almost no static power dissipation.

Question 24

If the transistor is in a socket, the first step in troubleshooting is to remove it and use and ohmmeter or plug it into a curve tracer.

Question 25

The pinch off voltage of a JFET is analogous to the cutoff voltage of a BJT.

Question 26

With the drain connected to a positive voltage and the source grounded, the JFET is biased off when the gate is connected to ground.

Question 27

In the fabrication of semiconductors, the material used is a

A) gaseous matter.
B) single crystal.
C) transistor substrate.
D) layer of crystals.
E) liquid crystal.

Question 28

The doping level in semiconductors relates to the

A) amount of impurities.
B) amount of P -type material.
C) size of the crystal structure.
D) amount of N -type material.

Question 29

A voltage reference diode is a

A) rectifier diode.
B) light emitting diode.
C) signal diode.
D) zener diode.
E) none of the above

Question 30

What type of diode(s) would typically be proposed to be used as a switch?

A) signal diode
B) light emitting diode
C) zener diode
D) rectifier diode
E) A and C

Question 31

-The symbol in this graphic is a

A) P -channel enhancement mode MOSFET.
B) N -channel depletion mode MOSFET.
C) P -channel depletion mode MOSFET.
D) N -channel enhancement mode MOSFET.

Question 32

A diode could be judged as properly functioning if it

A) conducted current in both directions.
B) did not dissipate heat.
C) conducted only when forward biased.
D) conducted current only when reversed biased.
E) none of the above

Question 33

The current that flows when a transistor is cut off is called

A) bias current.
B) leakage current.
C) depletion current.
D) base -emitter current.

Question 34

The formula for the turn -on time of a transistor switching from cutoff to saturation is

A) rise time plus delay time plus storage time.
B) rise time plus hold time plus delay time.
C) rise time plus storage time.
D) rise time plus delay time.
E) none of the above

Question 35

The construction of solid state relays creates advantages over electromechnical relays that include

A) faster operation.
B) no need for a socket.
C) no need for a heat sink.
D) impervious to electromagnetic interference.
E) less expensive.

Question 36

The transistor inverter is typically not used in conjunction with a

A) filter.
B) rectifier.
C) DC -to -DC converter.
D) digital -to -analog converter.
E) transformer.

Question 37

?

-In designing this four -resistor bias circuit, the AC gain is set by the ratio of

A) R_C to R_E.
B) R_E to R_C.
C) R1 to R2.
D) R1 to R_E.

Question 38

Match the input impedance with the device type

-Thousands of ohms

A) MOSFET
B) BJT Darlington pair
C) Zener
D) LED
E) JFET

Question 39

Match the input impedance with the device type

-Thousands of Megohms

A) MOSFET
B) BJT Darlington pair
C) Zener
D) LED
E) JFET

Question 40

Match the input impedance with the device type

-Millions of Megohms

A) MOSFET
B) BJT Darlington pair
C) Zener
D) LED
E) JFET

Question 41

Op amp characteristics can be tailored to fit a specific application by changing a few components.

Question 42

Input bias current of an op amp is the sum of the two input bias currents when the output is zero.

Question 43

The common -mode rejection of an op amp is expressed in decibels.

Question 44

The slew rate of an op amp is usually expressed in db per microsecond.

Question 45

Power dissipation of an op amp increases with increasing temperature.

Question 46

The closed loop gain of an inverting op amp is negative.

Question 47

An op amp in the non -inverting configuration has its negative input terminal at a virtual ground.

Question 48

The closed loop gain of an inverting and non -inverting of an op amp are equal when the external input resistor and the feedback resistor are equal.

Question 49

When a potentiometers is connected between the null inputs of an op amp, the input offset voltage can be partially eliminated by adjusting the potentiometers.

Question 50

In a summing amplifier, two or more resistors are connected to the positive input terminal of the inverting amplifier.

Question 51

When an op amp is used as a voltage -to -current converter, the load is connected in the feedback loop and the input signal is connected to the non -inverting input.

Question 52

When an op amp is used as a current -to -voltage converter, the load is connected in the feedback loop and the input signal is connected to the inverting input.

Question 53

The advantage of an op amp used as a comparator over a linear IC comparator is that the op amp comparator functions as a switch and provides a linear relationship between the input and output.

Question 54

Instrumentation amplifiers accurately output the difference between the inputs providing common -mode rejection.

Question 55

A Norton amplifier responds to a differential current, but the output of the Norton amplifier and the conventional op amp is voltage.

Question 56

The gain of the non -inverting CDA and the inverting CDA is the same except for sign.

Question 57

A low pass filter removes frequencies lower than the cutoff frequency.

Question 58

A second order low pass filter has a roll off of minus 40 db per decade.

Question 59

A change in frequency from 100 radians per second (rps) to 1000 rps causes a minus 10 db change in gain.

Question 60

The ratio of the resistors in the feedback circuit in an active filter determine the filter type.

Question 61

In a high pass filter, the pass band consists of frequencies below the cutoff frequency.

Question 62

A notch filter is another term for a band -pass filter.

Question 63

A band elimination filter eliminates all frequencies above and below the cutoff frequency.

Question 64

The discrete implementation amplifier can provide higher bandwidths than the monolithic implementation amplifier.

Question 65

For a high gain application, selecting an instrumentation amplifier with s low noise parameter is a key design consideration.

Question 66

When designing an inverting op amp circuit, the output offset phenomenon can be mitigated by_________

A) replacing the input resistor with a potentiometers
B) reducing the closed loop gain of the circuit
C) adding a resistor between the non -inverting input and ground
D) using low tolerance input and feedback resistors

Question 67

Common mode rejection is the ability of an op amp to reject

A) signals that are generated due to input offset voltage.
B) the effect of crosstalk.
C) the effect of unwanted signals from adjacent op amps.
D) signals that are simultaneously present at both inputs.

Question 68

The voltage fed back from an op amp output to its input is

A) in phase with the with the input.
B) a function of the open loop gain.
C) small compared to the input.
D) 90 degrees out of phase with the input.
E) none of the above

Question 69

Which of the following op amp configurations has the highest input resistance?

A) summing amplifier
B) non -inverting amplifier
C) inventing amplifier
D) differential amplifier

Question 70

The voltage follower is not used as a

A) isolation amplifier.
B) comparator.
C) low pass filter.
D) unity gain amplifier.
E) non -inverting amplifier.

Question 71

An op amp integrator is designed

A) with an op amp in the non -inverting configuration.
B) for detection of the transition of input pulses.
C) with a capacitor in the input circuit.
D) for an output that is proportional to the rate of change of the input.
E) none of the above

Question 72

?

-Examine these waveforms. The most accurate description the circuit that has the V_OUT for the V_IN would be a __________ op amp.

A) differential
B) integrator
C) comparator
D) differentiator
E) summing
Op amp.

Question 73

Filter design information that is typically not available on a bode plot is

A) cut -off frequency.
B) gain.
C) roll -off.
D) half -power point.

Question 74

The best circuit choice for rejecting the common -mode DC component on which a signal is riding is a

A) band elimination filter.
B) instrumentation amplifier.
C) Norton amplifier.
D) differential amplifier.
E) band pass filter.

Question 75

The coupling capacitor in CDA circuits is important because if its value is

A) too large the circuit gain will be increased.
B) too small the circuit gain will be decreased.
C) too large the circuit gain will be decreased.
D) too small the circuit gain will be increased.

Question 76

-This circuit depicts

A) a differentiator.
B) a first order high pass filter.
C) a first order low pass filter.
D) an integrator.

Question 77

Match the components with their function


-R3 and R4

A) determines characteristics of the low pass filter
B) determines characteristics of the high pass filter
C) determines the gain
D) determines the filter type

Question 78

Match the components with their function


-R1 and C1

A) determines characteristics of the low pass filter
B) determines characteristics of the high pass filter
C) determines the gain
D) determines the filter type

Question 79

Match the components with their function


-R2 and C2

A) determines characteristics of the low pass filter
B) determines characteristics of the high pass filter
C) determines the gain
D) determines the filter type