Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Instrumentation > Elect Theory N Safety > Flashcards

Elect Theory N Safety Flashcards

1
Q

2 main categories of resistors

A
  • fixed
  • variable
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

3 basic types of fixed resistors :

A
  • Composition resistors
  • film resistors
  • wire wound resistors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The most commonly used fixed resistor :

A

Composition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

2 types of variable resistors

A
  • Rheostats
  • potentiometer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Basic difference between rheostat and potentiometer

A

Rheostat has 2 connection points
Potentiometer has 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Res value
A) 2R2
B) 220k
C) 2M2

A

A) 2.2 ohm
B) 220 000 (×1000)
C) 2 200 000 (× million)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Resitor color code 1st color

A

1st digit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Resistor color code 2nd color

A

2nd digit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Redistor color code 3rd color

A

Multiplier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Resistor color gold
a) 4th position
B) 3rd position

A

A)+- 5%
B) .1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Resistor color code silver
A) 4th position
B) 3rd position

A

A)+- 10%
B) .01

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Resistor color code no 4th band

A

+- 20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Resistor color code black:
A) first color
B) second color

A

Both are 0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

If there are more than 4 color bands:

A

1 to 3) #s
4) multiplier
5) tolerance
6) temp coefficient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Resistor color code yellow,violet, red, silver rating

A

4700 +- 10% (4.7 k ohm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Res colors green,black,brown rating

A

500 ohms +- 20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

3 distinct ratings of resistors

A

A) resistance (ohms)
B) power (watts)
C) tolerance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Resistor color code

A

Black
Brown
Red
Orange
Yellow
Green
Blue
Violet
Grey
White
Gold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

A material with easily freed electrons is called

A

A conductor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Def: static electricity

A

Build up of charge in an insulated object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Static electricity:

A

Build-up of charge in an insulated object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

A ______ represents the quantity of charge of a huge # of electrons

A

Culomb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Def amp ,:

Current formula

A

Rate of movement of charges past a point

Current = quantity of charge/ time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Conventional current flows from ____ to _____

A

Positive to negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

If current flows from - to + it is _____ flow

A

Electron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Why dont you connect an ammeter in parallel:

A

The low resistance of the ammeter will cause a large current flow and blow the fuse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Voltage is derived :

A

From the measurement of difference in charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

6 sources of emf

A

1) magnetic
2) chemical
3) friction
4) heat
5) pressure
6)light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Formula for conductance

A

G = 1/R

30
Q

Ohms law

A

V / I ×r

31
Q

What force maintains a difference in charge?
Its abbreviation?

A

Electromotive force
Emf

32
Q

4 factors affecting conductor resistance

A

1) cross sectional area
2) length
3) type of material
4))temp of material

33
Q

Resistance is directly _____ to conductor length

A

Proportional

34
Q

Resistance is ______ to conductor cross sectional area

A

Inversely proportional

35
Q

For most materials increase temp causes:

A

Increased resistance

36
Q

At 20 degrees what is the resistivity of copper

A

1.72 × 10 ^-8

37
Q

At 20 degrees what is the resistivity of aluminum

A

2.83 ×10^-8 ohms

38
Q

Copper ohms per 1000m, how does it increase,?

A

3.27
Doubles every 3 gages ie:away 13 is 6.54, 16 is 13.08
Or goes up × 1.26 each gage

39
Q

Base unit for temp

A

Kelvin

40
Q

Base unit for amount of substance

A

A mol

41
Q

Conductor resistance formula:

A

Ohms = resistivity × length / area
Resistivity is in ohm- meters

42
Q

Temp resistance formula

A

R2 =R1(1+a(t2 -t1))
R1 initial temp res
a temp coefficient
T2 new temp
T1 initial temp

43
Q

Dielectric strength def,:

A

Voltage required to cause a breakdown in insulation

44
Q

Unit for dialectic stength

A

Volts per millimeter

45
Q

Mili def

A

10 ^-3

46
Q

Micro def

A

10 ^ -6

47
Q

Nano def :

A

10 ^-9

48
Q

Pico def

A

10 ^-12

49
Q

A copper conductor is 150m long and has a resistance of .76. Whats the cross sectional area?

A

1.72 ×10^-8 ×150m /.76
= 3.4× 10^-6 m^2
Or 3.4 mm^2

50
Q

To measure the ohms for volt drop

A

De energized check across the load

51
Q

Valence electrons for
- conductors
- insulators
- semi

A
  • 1 to 3 cond
  • 4 semi
  • 5 to 8 insul
52
Q

Every 3 db _____ the strength of the noise

A

Doubes

53
Q

3 power calcs

A

P = VI
P =( V ^2)/ R
P = I^2 R

54
Q

Min battery voltage after supplying amp hour rating?

A

91% of Max

55
Q

Voltage leads current in an _____ circuit

A

Inductive

56
Q

Current leads voltage in a _____ cct

A

Capacitive

57
Q

Series cct :
Res
Volt
Amps

A

Add ohms
I is same
V different

58
Q

Parallel cct
Res
Volt
Amps

A

1 over ( 1 / res 1) (1 / res 2)
Volts same
Current varies

59
Q

In a series cct if R1 ohms are 3x larger than R2 then R1 voltage is ______ than R2

A

3x larger

60
Q

Series cct voltage across closed switch

A

0v

61
Q

Series cct voltage across open switch

A

Applied voltage

62
Q

Kirchoffs voltage law states:

A

The algebraic sum of all voltages in a closed cct = 0

63
Q

Parallel cct:
RT = 15.
R1 = 30
R2 = 120
R3 = x

A

X = 40

64
Q

Parallel cct
E =12 v
R1 = 24
R2 = 24
R3 = 12
Rt =? It =? R1 I?

A

Rt = 6 ohms
It = 2a
R1 i = .5a

65
Q

Kirchoffs current law:

A

All the current values entering a junction must equal the current values leaving a junction

66
Q

Def : inductance

A

Property of a cct that opposes change in current

67
Q

Def induction

A

Process by which h a voltage is produced by the interaction of a conductor and a magnetic feild

68
Q

Amount of emf is directly proportional to change of flux is whos law

A

Faradays

69
Q

Current from an induced voltage develops a flux that opposes a change in the original flux is whos law

A

Lenz’s law

70
Q

With a coil what 4 factors up inductance

A

1) more turns
2) higher permeability
3) bigger core area
4) shorter path

Instrumentation (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions