Semiconductor Final Exam 2/25

_____ is the most commonly used semiconductor material

silicon

At room temperature, pure silicon crystals are poor _____; they behave like _______

conductors; insulators

In some applications, heat-sensitive devices are necessary. In these applications, ______ is used

germanium

In N-type material, _______ are the majority carrier and _____ are the minority carrier

electrons, holes

Pentavalent materials have atoms with ______ valence electrons and are used to make ______ material

five, N-type

Trivalent materials have atoms with ______ valence electrons and are used to make ______ material

three, P-type

In P-type material, _______ are the majority carrier and ______ are the minority carrier

holes, electrons

N- and P-type semiconductor materials have conductivity that is ______ pure semiconductor materials

much higher than

Current flow occurs only if the external voltage is _______ the barrier voltage

greater than

When the current flows from the N-type toward the P-type material, the diode is said to have a ______ bias

forward

When a diode is forward biased, the resistance is ______

low

In a diode that is ______ biased, the negative terminal of the external voltage source is connected to the N material, and the positive terminal is connected to the P material

forward

A PN junction diode is a ______-directional device

one

If the _______ is exceeded, a large reverse current flows, creating excess heat and damaging the diode

peak inverse voltage

The _____ junction method is the method most in use today

diffused

In packages for diodes rated at _____ A or less, the cathode is identified by a black, white or silver band on the end

three

If a diode shows both low forward and high reverse resistance, it is probably

shorted

If the diode measures both high forward and high reverse resistance, then it is probably

opened

When a reverse-biased voltage is applied that is high enough to cause breakdown in a zener diode, a high _____ flows

reverse current

The _______ of a zener diode is determined by the resistivity of the diode. This, in turn, is controlled by the doping technique used during manufacturing

breakdown voltage

A _______ is given by the diode manufacturer to determine the power rating at different temperatures from the ones specified in their tables

derating factor

Zener diodes with a breakdown voltage between four and five volts may have a _____ voltage-temperature coefficient

positive or negative

A zener diode can be used to stabilize or regulate voltage. For example, it can be used to compensate for power-line voltage changes or load-resistance changes while maintaining a constant

DC output

A transistor consists of ______ alternately doped regions

three

In a transistor, the barrier voltage is produced across the ______ junction

emitter-base

The reverse-bias voltage applied to the collector-base junction is usually ______ the forward-bias voltage across the emitter-base junction

much higher than

The _______ in the ohmmeter is the source of the forward- and reverse-bias voltage

battery

In a JFET, the U-shaped region is called the ______ and is flush with the upper surface of the substrate

channel

Because the gate-to-source voltage is reverse biased, the JFET has a(n) ______ input resistance

extremely high

______ are the best known of the thyristors

SCRs

A(n) ______ is basically a rectifier because it controls current in only one direction

SCR

To switch the SCR off, it is necessary to reduce the ______ voltage below the hold-on value, typically close to zero

anode-to-cathode

______ conduct both directions of AC current flow

TRIACs

A(n) ______ can be used as an AC switch

TRIAC

The most frequently used triggering device is the

DIAC

All transistor amplifiers require ________ voltage(s) for proper biasing

two

__________ materials have characteristics that fall between those of insulators and conductors

semiconductor

_________ is the process of sharing valence electrons, resulting in the formation of crystals

covalent bonding

A(n) ______ is created by joining N- and P- type materials together

diode

The region near the junction where the electrons and holes are depleted is called the

depletion region

When a voltage is applied to a diode, it is referred to as a(n) _______ voltage

bias

The most common transistor package identifier consists of the letters ______ followed by a number

TO

There are two methods for checking a transistor to determine if it is functioning properly: with a(n) ______ and with a transistor tester

ohmmeter

________ refers to locking onto one of two stable states

bistable

__________ is a method of obtaining an increases output by feeding part of the ouput back to the input

regenerative feedback

A TRIAC is equivalent to two SCRs connected in ________, back to back

parallel

________ are electronic circutis that are used to increase the amplitude of an electronic signal

amplifier