Flashcards in Electrical Elements Deck (158):

1

## What does a wire gauge represent?

### the diameter of the entire wire, bigger gauge number, smaller diameter and vice versa

2

## What are the common gauge numbers used in households?

###
10AWG - 5.261mm^2

12AWG - 3.309mm^2

14AWG - 2.081mm^2

3

## Superconductor is also known as?

### Cryogenic conductor

4

## What material is the best conductor of electricity?

### Silver, due to most number of free electrons per unit volume

5

## which metals are the best conductors of electricity

###
Pure silver

Pure copper

Pure gold

Aluminum

6

## What are wire-wound resistors?

### Uses metal alloys that are independent of temperature like manganin and constantan, and have an inductive property

7

## What are thin film resistors

### Deposited thin metal(Ceramic Metal) on an insulating support, Has High Resistance, Has no Reactive property

8

## What are carbon composition resistors?

### low wattage fixed type made from carbon, Its size is proportional to the power it can handle

9

## What is a rheostat?

### variable resistor with only two terminals, used in high power and high voltage, wire-wound(has inductive property)

10

## What is potentiometer

### variable resistor used for low power and low current application, has 3 terminals

11

## Resistors color code

###
1st significant, Second Significant, multiplier, tolerance,

Black Black 0

Boys Brown 1

Respect Red 2

Our Orange 3

Young Yellow 4

Girl Green 5

But BLue 6

Violeta Violet 7

Goes Gray 8

White White 9

12

## What does the reliability (5th) band in a resistor indicate?

### Reliability (in percent of failure per 1000 hours of use)

13

## It is the fundamental source of electrical energy developed through the conversion of chemical or solar energy

### Cell

14

## Combination of two or more cells

### Battery

15

## These are not rechargeable cells, AND DO NOT HAVE RESISTANCE

### Primary Cell

16

## These are rechargeable cells AND HAVE RESISTANCE

### Secondary Cells

17

## Two common rechargeable cells

###
Lead-Acid used in automobiles

Nickel-Cadmium used in calculators/tools/photoflash units

18

## Carbon-zinc (Leclanche): Classification and output voltage

### Primary/1.5V designed for 70 degrees Farenheit operation

19

## Zinc Chloride: Classification and output voltage

### Primary/1.5V Heavy Duty type

20

## Manganese Dioxide (alkaline): Classification and output voltage

### Primary or Secondary/ 1.5V has low internal resistance

21

## Mercuric Oxide: Classification and output voltage

### Primary/1.35V

22

## Silver Oxide: Classification and output voltage

### Primary 1.5V

23

## Lead Acid: Classification and output voltage

### secondary 2.1V

24

## Ni-Cd: Classification and output voltage

### Secondary 1.25V

25

## Nickel-Iron(Edison Cell): Classification and output voltage

### Secondary 1.2V

26

## Nickel-Metal hydride: Classification and output voltage

### Secondary 1.2V, does not suffer memory effect

27

## Silver-Zinc: Classification and output voltage

### Secondary 1.5V

28

## Silver Cadmium : Classification and output voltage

### Secondary 1.1V

29

## Battery Life expression

### Battery Life(Hr)=Ampere-Hour rating(Ah)/Amperes Draws

30

## Also called as Crowfoot cell/gravity cell/wet cell used in operating telegraphs and door bells

### Daniel Cell

31

## Also called as galvanic Cell, Named after Luigi Galvani

### Voltaic Cell

32

## Primary Cell with high output voltage, long shelf life, low weight and small and can provide 10x more energy

### Lithium Cell

33

## Very good power to weight ratio, often found in high end laptop

### Lithium-ion battery

34

## Used in electric vehicles

### Metal-chloride battery

35

## Other name for a capacitor

### Condenser

36

## Unit of capacitance is named after?

###
Michael Faraday

37

## What is the reciprocal of capacitance?

### Elastance, unit is daraf

38

## What is Gauss Theorem

### The total electric flux extending from a closed surface is equal to the algebraic sum of the charges inside the closed surface

39

## Gauss Theorem mathematical Expression

###
ψ = Q

Wb(Unit of flux) = C(unit of charge)

ψ - # Electric Flux Lines

Q - Charges inside an enclosed surface

40

## Electric Flux Density Formula

###
D=ψ/Area

where: ψ=total flux, Mx or Wb

A=Area, cm^2 or m^2

1 Tesla= 1Wb/m^2

1 Gauss = 1 Maxwell/cm^2

41

## Electric Field Intensity Formula

###
E=F/Q

F= Newtons,

Q=Charge, Coulomb

in capacitors:

E=V/d

where V=voltage, d=plate separation

42

## First law of Electrostatics

### unlike charges attract each other while like charge repel each other

43

## Second law of elecrostatics

### the force of attraction or repulsion between charges is directly proportional to the product of the two charges but inversely proportional to the square of distance between them

44

## Second law of statics mathematical formula

###
F = kq1q2/r^2

k=1/(4π*εo*εr)

εo=absolute permittivity, shift constant 32

45

## What is permittivity?

###
It is the ratio of electric flux density to the electric field strength

ε=D/E (in Farads/m)

46

## relative permittivity (εr) of teflon

### 2.0

47

## relative permittivity (εr) of paper, paraffined

### 2.5

48

## relative permittivity (εr) of mica

### 5.0

49

## relative permittivity (εr) of transformer oil

### 4.0

50

## It is the voltage required per unit length to establish conduction in a dielectric

### Dielectric Strength or breakdown voltage

51

## Dielectric strength of Air

###
75 V/mil

OR

3 x 10^6 (V/m)

52

## Dielectric strength of Barium-strontium titanite(ceramic)

###
75 V/mil

OR

3 x 10^6 (V/m)

53

## Dielectric Strength of transformer oil

### 400 V/mil

54

## Formula for the energy stored in a capacitor

### Wc=1/2*CV^2 or Q^2/2C

55

## What is the electrical definition of capacitance?

###
Charge per unit volt

C=Q/V

Q=charge

V=Voltage

56

## Formula for capacitance based on physical construction

###
C=(n-1)*(εA/d)

n=number of parallel plates

ε=permittivity

A=plate area

d=distance bet. plates

57

## Series Capacitor's total capacitance

### Ct = 1 / ( {1 / C1} + {1 / C2} + ....)

58

## Total charge in a series capacitor

### Qt=Q1=Q2=Q3

59

## Identical capacitors in series total capacitance

### Ct=C/n

60

## Total capacitive reactance on series capacitors

### Xct=Xc1+Xc2+Xc3..

61

## Parallel Capacitor Total capacitance

### Ct= C1 + C2 + C3

62

## Parallel Capacitor identical capacitors capacitance

### Ct = nC

63

## Parallel Capacitor total charge

### Qt=Q1+Q2+Q3...

64

## Parallel Capacitor capacitive reactance

### Xct = 1 / ( {1/Xc1{ + {1/Xc2} + {1/Xc3} )

65

## capacitance of parallel-plate capacitor (with multiple dielectrics in between)

###
C = εoA / ( [d1/εr1] + [d2/εr2] + [d3/εr3] )

d1,d2,d3 - dielectric thickness within the parallel plates

εr1, εr2, εr3 - Relative Permittivity of the dielectrics

66

## Cylindrical capacitor formula

###
C = [ (εr*l) / (41.4log(b/a)) ] x10^-9

a=inner diameter of single core cable conductor

b=outer diameter

l=length of the cylindrical capacitor

67

## Capacitance of an isolated Sphere

###
C=4*π*ε*r

r=radius of isolated sphere

68

## Capacitance of concentric sphere, out sphere is grounded

###
C=4*π*ε(ab/(b-a))

a=inner radius

b-outer radius

69

## Capacitance of concentric sphere, inner sphere is grounded

###
C=4*π*ε*b^2/(b-a)

a=inner radius

b-outer radius

70

## It is a measure of the ability of a coil to oppose any change in current through the coil. and store energy in the form of magnetic field

### Self Inductance/inductance

71

## Formula of inductance in terms of physical dimensions

###
L=(μ)n^2A/l

μ=permeability of the core, H/m

N=number of turns

A=area of core, m^2

l-mean length of the core

72

## Formula of inductance in terms of electrical definition

### L= Hd(Φ)/di

73

## Energy stored by an inductor

### Wl=0.5*L*(I^2)

74

## What is faraday's law

###
The voltage induced across a coil of wire equals the number of turns in the coil times the rate of change of magnetic field

Einductor = Nd(Φ)/dt = Ldi/dt

75

## What is lenz's law?

### An induced voltage effect is always such as to oppose the cause that produced it

76

## Lenz's law mathematical expression

### Einductor = - N*d(Φ)/dt

77

## Series inductors without mutual inductance

### Lt=L1+L2+L3..

78

## Series inductors with mutual inductance

###
M=k*sqrt( L1 * L2 )

Lt(aiding) = L1 + L2 + 2M

Lt(opposing) = L1 + L2 - 2M

k-coupling coefficient

k = 0 if minimum(Blocked by Dielectric)

k = 1 if maximum(Uses Iron Core)

79

## Parallel inductors total inductance, aiding

### Lt(aiding)=(L1*L2 - M^2) / (L1 + L2 - 2M)

80

## Parallel inductors total inductance, opposing

### Lt(opposing)=(L1*L2 - M^2) / (L1 + L2 + 2M)

81

## Inductance of long coil

### L=(μ)N^2*A/l

82

## Inductance of short coil

###
L=(μ)N^2*A/(l+.45d)

d - diameter of short coil

83

## Inductance in Toroidal coil with rectangular cross section

###
L=(μ)(N^2h / 2π) * ln (d2 / d1)

h=thickness, m

d2,d1=outer and inner diameters respectively

L - in μH

84

## Inductance of Circular Air core

###
L=0.07(RN)^2/(6R+9l+10b)

R=d/2+b/2

d=core diameter,in

b=coil buildup,in

l = coil thickness, in

L - in μH

85

## Inductance of magnetic core coil, no air gap

###
L = 0.012N^2(μ)A /lc

A - Area in cm^2

lc - magnetic path length (cm)

L - in μH

86

## Inductance of magnetic core coil, air gap

###
L = 0.012N^2*A /(lg + lc/(μ))

A - Area in cm^2

lc - magnetic path length (cm)

lg - gap length(cm)

L - in μH

87

## The unit of electrical power is named after>

### James Watt

88

## Equivalent power (in watts) of 1 HP

### 1HP=746W

89

## Millman's Theorem

### the voltage across the parallel combination is the ratio of the algebraic sum of currents to the internal conductance

90

## Power transfer efficiency

### n=Rl/(Rl+Rsource)x100%

91

## Inferred Absolute Zero Temperature of Copper

### T(iazt) = -234.5 °C

92

## Inferred Absolute Zero Temperature of Silver

### T(iazt) = -243 °C

93

## When a Conductor is cooled to the Inferred Absolute Zero Temperature, its resistance is __________

### zero

94

## Resistivity of Copper (ρ20 in R = ρL/A)

### ρ20 = 1.7 x 10^-8 Ω-meters

95

## Resistivity of Silver (ρ20 in R = ρL/A)

### ρ20 = 1.5 x 10^-8 Ω-meters

96

## Resistivity of Gold (ρ20 in R = ρL/A)

### ρ20 = 2.4 x 10^-8 Ω-meters

97

## Resistivity of Aluminum (ρ20 in R = ρL/A)

### ρ20 = 2.6 x 10^-8 Ω-meters

98

## Thermistors are usually used as ______

### Sensors

99

## Thermistors are either _____ or ______

### PTC, NTC

100

## In a Light Dependent Resistor, its resistance is (Directly/Inversely) Proportional to the illumination on the device

### Inversely

101

## When does the resistance of a Light Dependent resistor reach maximum value?

### When Completely Dark

102

## What do you call the maximum resistance of a Light Dependent Resistor?

### Dark Resistance

103

## In a Voltage Dependent Resistor, its resistance is (Directly/Inversely) Proportional to the Voltage Across the device

### Inversely

104

## Voltage Dependent Resistors are usually used for _________

### Circuit Protection

105

## The Cross Sectional Area of a conductor assumed by the unit of Circular Mil looks like a _____

###
Square ¯\_(ツ)_/¯

CM = d^2

d - diameter of cable

106

## The Cross Sectional Area of a conductor assumed by the unit of Square Mil looks like a ______

###
Circle ¯\_(ツ)_/¯

SM = (π/4)*CM

= (π/4)*d^2

d - diameter of cable

107

## Mil is short for ______

### Milli-inch (1 x 10^-3)

108

## When 4th Band of a resistor has no color, what is the Tolerance%? And the tolerance Letter Designation?

###
+- 20% (M)

109

## When 4th Band of a resistor has the color Brown, what is the Tolerance%? And the tolerance Letter Designation?

###
+- 1% (F)

110

## When 4th Band of a resistor has the color Red, what is the Tolerance%? And the tolerance Letter Designation?

###
+- 2% (G)

111

## When 4th Band of a resistor has the color Green, what is the Tolerance%? And the tolerance Letter Designation?

###
+- 0.5% (D)

112

## When 4th Band of a resistor has the color Blue, what is the Tolerance%? And the tolerance Letter Designation?

###
+- 0.25% (C)

113

## When 4th Band of a resistor has the color Violet, what is the Tolerance%? And the tolerance Letter Designation?

###
+- 0.1% (B)

114

## When 4th Band of a resistor has the color Gold, what is the Tolerance%? And the tolerance Letter Designation?

###
+- 5% (J)

115

## When 4th Band of a resistor has the color Silver, what is the Tolerance%? And the tolerance Letter Designation?

###
+- 10% (K)

116

## When 4th Band of a resistor has the color Gray, what is the Tolerance%? And the tolerance Letter Designation?

###
+- 0.05% (A)

117

## When 5th Band of a resistor has the color Brown, what is the Reliability?

### 1%

118

## When 5th Band of a resistor has the color Red, what is the Reliability?

### 0.1%

119

## When 5th Band of a resistor has the color Orange, what is the Reliability?

### 0.01%

120

## When 5th Band of a resistor has the color Yellow, what is the Reliability?

### 0.001% (MOST RELIABLE)

121

## When the 3rd Band of a resistor is Gold, What is the Multiplier used?

### x 10^-1

122

## When the 3rd Band of a resistor is Silver, What is the Multiplier used?

### x 10^-2

123

## When the 3rd Band of a resistor is Pink, What is the Multiplier used?

### x 10^-3

124

## The property of a battery that determines how efficient its quantity of storage is

### Ampere-Hour (AH) efficiency

125

## Formula for AH Efficiency(η)

###
η(AH) = AH(discharge) / AH(charge)

η(AH) = I(d)*t(d) / I(c)*t(c)

I(d) and I(c) - Discharging/Charging Current

t(d) and t(c) - Discharging/Charging time

126

## The property of a battery that determines how efficient its storage of Energy is

### Watt-Hour Efficiency (WH)

127

## Formula for WH(Watt-Hour) Efficiency(η)

###
η(WH) = WH(discharge) / WH(charge)

η(WH) = P(d)*t(d) / P(c)*t(c)

η(WH) = [ V(d)*I(d)*t(d) ] / [ V(c)*I(c)*t(c) ]

but η(AH) = I(d)*t(d) / I(c)*t(c)

---------------------------------------------

Therefore: η(WH) = η(AH) * (V(d) / V(c))

---------------------------------------------

V(d) and V(c) - Discharging/Charging Voltage

P(d) and P(c) - Discharging/Charging Power

I(d) and I(c) - Discharging/Charging Current

t(d) and t(c) - Discharging/Charging time

128

## What does Temperature resistance coefficient of a material describe?

### When temperature increases by 1 °C, the resistance increases by (Temperature resistance coefficient) Ohms

129

##
Temperature resistance coefficient (α20) of:

Gold

### 3.7 x 10^-3 ( /°C)

130

##
Temperature resistance coefficient (α20) of:

Silver

### 3.8 x 10^-3 (/°C)

131

##
Temperature resistance coefficient (α20) of:

Copper

### 3.93 x 10^-3 ( /°C)

132

##
Temperature resistance coefficient (α20) of:

Aluminum

### 4 x 10^-3 ( /°C)

133

##
Temperature resistance coefficient (α20) of:

Nichrome

### 0.4 x 10^-3 (/°C)

134

##
Temperature resistance coefficient (α20) of:

Manganin

### 0.03 x 10^-3 ( /°C)

135

##
Temperature resistance coefficient (α20) of:

Constantan

### 0.008 x 10^-3 ( /°C)

136

## Relative Permittivity (εr) of rubber

### 3

137

## Relative Permittivity (εr) of Pyrex

### 5.6

138

## Dielectric Strength (V/m) of Teflon

### 60 x 10^6 (V/m)

139

## Dielectric Strength (V/m) of Rubber

### 27.55 x 10^6 (V/m)

140

## Dielectric Strength (V/m) of Paper

### 16 x 10^6 (V/m)

141

## Dielectric Strength (V/m) of Mica

### 197 x 10^6 (V/m)

142

## Dielectric Strength (V/m) of Pyrex

### 14 x 10^6 (V/m)

143

## Capacitor Color Coding

###
Same as Resistance color coding

Although, for 4th Band Tolerance :

Green is 5% in capacitors, not like 0.5% in resistors

Grey is 80%-20% in capacitors

White is 10% in capacitors

Red is 2% in capacitors

yellow is 3% in capacitors

(No reliability)

144

## When reading capacitance values, the unit represented by a colored/numbered code is in ___________

### PICO farads (pF)

145

## Capacitor Number Coding

###
Capacitor Nimber Coding contain 4 characters:

Char. 1 and 2, are the 1st and 2nd digit of capacitance value

Char. 3 is the multiplier

Char 4 is the Letter Designation for Tolerance(Same as Resistor)

146

##
Capacitor Number Coding:

When 3rd Char is equal to 0, the multiplier used for the capacitance is:

### 1 pF

147

##
Capacitor Number Coding:

When 3rd Char is equal to 1, the multiplier used for the capacitance is:

### 10

148

##
Capacitor Number Coding:

When 3rd Char is equal to 2, the multiplier used for the capacitance is:

### 100

149

##
Capacitor Number Coding:

When 3rd Char is equal to 3, the multiplier used for the capacitance is:

### 1000

150

##
Capacitor Number Coding:

When 3rd Char is equal to 4, the multiplier used for the capacitance is:

### 10,000

151

##
Capacitor Number Coding:

When 3rd Char is equal to 5, the multiplier used for the capacitance is:

### 100,000

152

##
Capacitor Number Coding:

When 3rd Char is equal to 6 or 7, the multiplier used for the capacitance is:

### N/A

153

##
Capacitor Number Coding:

When 3rd Char is equal to 8, the multiplier used for the capacitance is:

### 0.01

154

##
Capacitor Number Coding:

When 3rd Char is equal to 9, the multiplier used for the capacitance is:

### 0.1

155

## Alternative Formula for Mutual Inductance(Given aiding and opposing inductance)

###
M = (Lta - Lto) / 4

Lta -Total aiding Inductance

Lto - Total opposing Inductance

156

## Inductance of Rectangular Air core

###
L = 0.07*(CN)^2 / (1.908C + 9l +1 0b)

C= d + Y + 2b

d=core hole length,in

Y=core hole width, in

b=coil buildup,in

l = coil thickness

L - in μH

157

## Inductor Color Coding

### Same as Resistor( 1st, 2nd, Multiplier, Tolerance)

158