Ch. 16 Electric Properties

Question 1

Ohms Law

Answer 1

I = V / R

Question 2

Resistivity formula

Answer 2

P = R * A / L

Question 3

Conductivity formula

Answer 3

σ = 1 / P

Question 4

Valence band

Answer 4

Outermost filled band

Question 5

Conduction band

Answer 5

Next available enrgy level

Question 6

Imperfections increase…

Answer 6

Resistivity

Question 7

Imperfection examples

Answer 7

Grain boundaries, Pores, Impurities, Dislocations, Vacancies

Question 8

Metal resistivity increases w/:

Answer 8

T, %impurities, %cold work(causes dislocations)

Question 9

Matthiesens rule

Answer 9

Ptotal = Pthermal + Pimpurity + Pdef

Question 10

Pthermal =

Answer 10

P0 + aT (all constants exept T)

Question 11

T in metals is directly proportional to: (why does T increase resistivity)

Answer 11

Vibrations = Electron scattering

Question 12

%CW is directly proportional to

Answer 12

dislocations = P0

Question 13

Pimpurity =

Answer 13

A * Ci * ( 1 - Ci) — Ci = impurity concentration)

Question 14

Pimpurity for phased =

Answer 14

PaVa + PbVb

Question 15

Charge carriers in insulators & instrinsic semiconductors

Answer 15

Free electrons and holes in valence bands

Question 16

σ formula for insulators

Answer 16

σ = n *|e| * μe (electron mobility) + p * |e| * μh

Question 18

for intrinsic semiconductors T is proportional to

Answer 18

σ (opposite to metals)

Question 19

σ of undoped intrsinic semiconductors formula

Answer 19

σ proportional to exp ( - Egap / ( k * T ) )

Question 20

Types of semiconductors

Answer 20

Intrinsic & Extrinsic

Question 21

Relationbetween n and p in intrinsic semiconductors

Answer 21

n = #p

Question 22

Extrinsic semiconductors

Answer 22

n != #p

Question 23

N type

Answer 23

(n > p)

Question 24

P type

Answer 24

(n < p)

Question 25

Extrinsic semiconductors vs T

Answer 25

weird graph , extrinsic looks like “S”, intrinsic is exponential

Question 26

P - N Rectifying Junction

Answer 26

P type and N type semiconductors together