MCQs SOLID STATE DEVICES

Carbon

A semiconductor element that is mainly used in the production of resistors

Three valence electrons

The number of valence electrons of gallium

Five valence electrons

The number of valence electrons of arsenic

Ionization potential

This is the potential required to remove a valence electron from the atomic structure

IIIA, IVA, V

What groups do most semiconductors belong?

1.5×10 raised to 10

At room temperature there are approximately this value of free carriers in a 1 cm cube of intrinsic silicon

Intrinsic carriers

The free electrons in a material due only to external causes are referred to as

2.5×10 raised to 13

At room temperature there are approximately this value of free carriers in a 1 cm cube of intrinsic silicon material

Relative mobility

This is the ability of the free carriers to move throughout the material

Drift velocity

the average velocity at which free charge carriers move through a conductor because of an applied electric field.

Doping compensation

The addition of donor impurities to a P-type semiconductor or of acceptor impurities to an n- type semiconductor

Transistor, junction, diode, solid state device

These are electronic device devices, which operates by which of the movement of electrons within a solid piece of semiconductor material

It decreases with an increase in light intensity

In addition to rectifying properties, selenium has the pro of being light sensitive how is selenium resistance affected by light?

Czochralski Process

This is a method of crystal growth used to obtain single crystals of semiconductors

Higher

• The farther an electron is from the nucleus, the ____ Is the energy state

• It is farther

• It has less attraction

• It has less negative potential energy

The breaking of covalent bonds

What process takes place within the semiconductor to cause hole flow?

For high temperature and high power requirement of semiconductors, the material used is

Silicon carbide

The energy difference across the forbidden gap

What determines whether the assorted material with as a conductor semiconductor or an insulator?

Edison effect

The emission of electrons from hot bodies

Lossev effect

This is the radiation that results from the recombination of charge carriers injected in a PN or PIN Junction, which is biased in forward direction

10^12

At room temperature, an intrinsic silicon material will have about one free electron for every ___ atoms

Less than 100V - 400V max

This is the breakdown voltage of Germanium

Vt = kT/q

Thermal voltage formula

Intrinsic

A material which has an equal number of electron hole pairs and conducting electrons is known as what type of semiconductor material

Trivalent

The semiconductor doping impurities of arsenic, antimony and bismuth are classified as what type of impurities

Neutrally charged. This is because the holes in the electrons just allows current flow not make it charged

P-type germanium and n-type silicon is ___ charged.

Reverse saturation current

The current that exists under reverse bias condition

Open switch

A reversed bias diode is like a

1N

The part number for a diode will always begin with the prefix

1 PN Junction

The diode prefix 1N, the number one indicates

Photocells

Selenium works especially well in

2.5mV

In the forward, bias region, the characteristics of a silicon diode shifts to the left at a rate of this value per centigrade degree increase in temperature

10

In the reverse bias region, the reverse saturation current of a silicon diode doubles for every ____ degrees Celsius rise in temperature

higher

The lower the Q point of operation, the ___ is the AC resistance

Galena

Early semiconductor diets are made mostly of minerals like

0.2V

Silicon has a built-in potential of 0.7 V Germanium is 0.3 V while Schottky has

Avalanche diodes

These are diodes which operates in reverse breakdown voltage

6.2V

Avalanche diodes, has breakdowns of about

Esaki diode

Other name for tunnel diode

Quantum tunneling

Tunnel diode exhibits negative resistance, which is caused by

Trickle charging

This is when charging does not occur during the entire cycle, but only when the charging voltage is more than the voltage of the battery

Inductive kick

Trying to change the current, one inductive element took quickly may result in this which could damage surrounding elements

Snubber

One of the cheapest but most effective ways to protect the switching system is to place a capacitor called ___ across the coil

Decrease it

How does forward biasing affect junction resistance?

They move away from the junction

When the PN Junction die is reversed, biased what happens to the majority carriers

Zeroing

This is a process whereby an applied form of zero average value is changed to one that has a DC level.

Voltage regulator

Avalanche voltage is routinely exceeded when a PN junction acts as E

Barrier Junction

The placing of an impurity on a semiconductor of the opposite impurity and fusing the two together produce what type of semiconductor junction

Depletion region

After the junction combination process has reached equilibrium. What is the area that surrounds the junction called?

As mixers, as switches, as detectors

Signal diodes are used for which of the following purposes

CR3

This Alphanumeric code correctly identifies the diode, crystal rectifier number 3 in a circuit

Do not pry the diode from the circuit, do not use excessive heat to remove the diode, do not remove the dial from the circuit while voltage is applied

When replacing a diode in a circuit, which of the following safety precautions should you observe in removing the diode from the circuit?

Two equal voltages from one transformer

The purpose of a center tap in a transformer is to provide

Ripple frequency formula

Vave = Vp / pi

Average voltage output of a halfwave rectifier

Vave = Vp*(2/pi)

Average voltage output of a full wave rectifier

RC capacitor input

What type of filter is the most basic power supply filter?

0%

In a voltage regulator, what percent of regulation would be ideal?

Either the load has infinite resistance or it is open

A no-load condition means that

Power supply percent of regulation formula

The peak value of the rectified voltage

The ideal DC output voltage of a capacitor input filter is equal to

$$r=\frac{Vrms(ripple)peak-to-peak}{Vdc}$$

Ripple factor formula

$$Vrip=\frac{Idc}{fC}=\frac{(\frac{Vdc-pp}{Rload})}{fC}$$

Ripple voltage formula

Changes in output, voltage, and input voltage

Line regulation is determined by

Changes in low current and output voltage

Low regulation is determined by

Temperature of operation

The zener potential of a zener diode is very sensitive to the

Zener effect

Which breakdown theory explains the action that takes place in a heavily dope PN junction with reverse bias below 5 V

Zener potential

The reverse breakdown voltage of a semiconductor diode will increase or decrease with temperature depending on the

More positive than the anode

The cathode of a Zener diode in a voltage regulator is normally

Zener breakdown

If a certain zener diode has a voltage of 3.6 V it operates in

Change in Zener voltage divided by the change in Zener current

Formula for the impedance of a Zener diode

It will increase

An increase in reverse bias of a varactor will have what effect on the width of the depletion region

It will decrease

What happens to the capacitance of a varactor diode as the reverse bias is increased

As a tuning device

In electronic circuits, how is the varactor used?

Reverse

What would a varactor be normally biased?

Ge and GaAs

What are the two materials used with tunnel diodes?

Tunnel / Esaki diodes

Is a heavily doped semiconductor p-n junction that uses quantum tunneling to let current flow at very low voltages. It shows negative resistance, meaning current drops as voltage rises.

No minority carries

What makes Schottky diodes high speed types?

A CMOS integrated circuit

Requires very little power to function

The phase of an applied ac signal

This is an unimportant factor concerning the frequency at which a PN Junction will work effectively

Can cause objectionable signal distortion

A diode audio limiter circuit

A microwave communications device

A Gunnplexer can be used as a

Gunnplexer

a compact microwave transceiver module that combines a Gunn diode oscillator (to generate a microwave signal) and a Schottky diode mixer (to receive signals) inside a single waveguide cavity.

Computer card readers, photographic light meters, optic scanning equipment

These are the uses of photodiodes

Photocell

This is the device which is similar in operation to a photodiode

Infrared

Diodes constructed of GaAs emit light in the ___ zone

Combination of Blue LED with yellow Scintillator Coat / combination of 3 LEDs

White LED is normally made of

Energy bandgap

The wavelength and frequency of light of a specific color are directly related to

Decreases with light intensity when reversed bias

The internal resistance of a photodiode

Optoisolator

Suppose you want a circuit to operate in a stable manner when the load impedance varies. you might consider a coupling method that employs

Electron energy level changes

Admission of energy in an IRED INFRARED EMITTING DIODE is caused by

Point contact

What term is used for a semiconductor that has three or more elements?

They generate less noise, they handle more power, they provide higher current and voltage gain

Junction transistors have replaced point contact transistors for the following reasons

This is the emitter in the type of transistor

In a schematic, what is indicated by the angular line with the arrowhead in the direction of the arrow

Five

GaAs transistor has _____ times the operating speed of silicon Si

Passivating

What is the layer which protects junctions in transistors called?

Overlay

What is the name of the type of high frequency transistors

0.92 - 0.998

Alpha typically extends from this range of values

AC alpha

This is formally called the common base, short circuit, amplification factor

50-400

Beta typically extent from about this range, but mostly in the mid range