Exam 1

Question 1

What is a conductor

Answer 1

element with nearly empty outer orbit

Question 2

what is an insulator

Answer 2

materials with no room for free electrons in the outer orbit

Question 3

what is a semiconductor

Answer 3

materials that are between conductors and insulators (Exactly half of orbit full)

Question 4

ferrous metal characteristics

Answer 4

contains mostly iron
little corrosion resistance

Question 5

What theory does the left hand rule go with

Answer 5

electron theory

Question 6

what theory does the right hand rule go with

Answer 6

convention theory

Question 7

what is a relay electromagnet

Answer 7

has a fixed core, low strength

Question 8

what is a solenoid

Answer 8

moveable core, high strength

Question 9

What is electromagnetic induction

Answer 9

when an electrical voltage / current I produced using magnetic fields and motion

Question 10

** three necessary elements for electromagnetic induction **

Answer 10

magnetic field
conductor
motion between mag field and conductor

Question 11

what is flux

Answer 11

a magnetic field

Question 12

What determines factor of produced voltage / current

Answer 12

strength of magnetic field
number of coils
speed of motion between magnet and coil

Question 13

What is Ohms Law

Answer 13

E = I * R

Question 14

What is I in Ohms Law

Answer 14

current, measured in amps

Question 15

What is R in Ohm’s Law

Answer 15

resistance, measured in ohms

Question 16

What is E in Ohms Law

Answer 16

electromotive force, measured in volts

Question 17

what is a resistor

Answer 17

component to stop current from flowing
made of metal wire or carbon
maintains stable resistance over various environmental conditions

Question 18

what is a common term for a conductor

Answer 18

a wire

Question 19

positive side of a diode

Answer 19

anode

Question 20

negative side of a diode

Answer 20

cathode

Question 21

three important features of a switch

Answer 21

contacts
ratings
method of operation

Question 22

pole

Answer 22

number of input contacts

Question 23

throw

Answer 23

number of output contacts

Question 24

single pole single throw SPST

Answer 24

on-off switch

Question 25

momentary on-off

Answer 25

push to make SPST returns to normally open (off) when released

Question 26

What is a magnetic field created through a current likely used to power In an aircraft

Answer 26

relay switches

Question 27

what is a transformer

Answer 27

device to increase or decrease voltage in an AC circuit using electromagnetic induction

Question 28

Advantages of relays

Answer 28

Can switch AC and DC Can switch higher voltages Often better for large currents Can switch many contacts at once

Question 29

disadvantages of relays

Answer 29

Big and heavy Slow Use more power

Question 30

outside of strength, what's a big difference between solenoids and relays

Answer 30

solenoids can be used for mechanical functions due to their moveable core

Question 31

what is a wire

Answer 31

single strand

Question 32

what is a cable

Answer 32

a collection of wire

Question 33

skinny wires have a (higher or lower) number

Answer 33

higher

Question 34

shielded wire

Answer 34

central wire carries signal, metallic shield (copper) connected to 0V

Question 35

coaxial cable

Answer 35

designed to carry high frequency signals

Question 36

two sets of wires in aviation typically use

Answer 36

terminal strips

Question 37

what are the pros of connectors

Answer 37

smaller and lighter than terminal strips immune to moisture, dirt, and vibration

Question 38

is solder a wire

Answer 38

no it is a filler made of lead and tin

Question 39

what was the first battery

Answer 39

voltaic pile 1799 Alessandro Volta

Question 40

primary cell

Answer 40

non reversible reaction not rechargeable can produce current immediately on assembly

Question 41

secondary cells

Answer 41

reversible reactions designed for use, recharge lower energy density than primary good for high-drain application

Question 42

wet cell

Answer 42

liquid electrolyte must be vented as gas is produced

Question 43

common dry cell has a nominal voltage of

Answer 43

1.5 volts

Question 44

dry cell composition

Answer 44

anode = zinc cylindrical pot cathode = carbon central rod electrolyte = ammonium chloride paste

Question 45

benefits of VRLA battery

Answer 45

low maintenance does not require regular water addition cannot spill

Question 46

what is a Gell cell battery

Answer 46

"recominant battery" creates oxygen in positive and hydrogen in negative to create water which prevents water loss

Question 47

why do VRLA sometimes have a safety pressure relief valve

Answer 47

In case hydrogen production rate becomes too high

Question 48

what modern batteries do aircraft use

Answer 48

secondary cell 24 volt lead

Question 49

advantages of lead-acid batteries

Answer 49

less expensive

Question 50

disadvantage of lead acid batteries

Answer 50

must be checked and replaced more often, less power to weight ratio

Question 51

advantages of nickel cadmium batteries

Answer 51

greater power to weight ratio CCV remains constant

Question 52

How does a nickel cadmium battery look

Answer 52

several layers of anode ad cathode material rolled into a cylindrical shape

Question 53

where are nickel cadmium batteries used

Answer 53

transport and commercial aircraft

Question 54

disadvantage of nickel cadmium battery

Answer 54

near constant voltage makes it hard to detect low battery

Question 55

downside of lithium ion batteries

Answer 55

prone to thermal runaway

Question 56

upside of lithium ion batteries

Answer 56

best energy to weight ratio no memory effect operate at higher voltages

Question 57

how do generators and alternators generate electricity

Answer 57

electromagnetic induction

Question 58

wire rotates inside the magnet (or visa versa)

Answer 58

generator (alternator)

Question 59

do generators produce AC or DC

Answer 59

AC

Question 60

what is the armature

Answer 60

main current carrying electrical winding receives induced voltage / current

Question 61

what is the commutator

Answer 61

connects armature to generator changes AC to DC

Question 62

what are the brushes

Answer 62

electrical contacts which touch the commutator and provide a current path for the power to leave the rotating armature

Question 63

rectifier

Answer 63

AC to DC

Question 64

inverter

Answer 64

DC to AC

Question 65

how are DC alternators similar to DC generators

Answer 65

change mechanical energy into electrical produce electrical power through electromagnetic induction produce AC and change it to DC

Question 66

how do DC alternators create current

Answer 66

use field windings which are rotating driven by the engine armature stationary

Question 67

how do DC generators create current

Answer 67

permanent magnet field armature windings are rotating

Question 68

Alt vs Gen

Answer 68

alternator supplies power through direct contact generator supplies power through commutator and brush assembly which makes an unreliable connection

Question 69

Alt / Gen construction

Answer 69

armature - where voltage is produced Field winding - creates magnetic field rectifier - changes AC to DC

Question 70

arrow side of the diode is (+ or -)

Answer 70

negative (where arrow is pointing)

Question 71

why are alternators more reliable

Answer 71

needs less maintenance technicians able to replace components

Question 72

what does the voltage regulator do

Answer 72

controls field strength keeps generator output at necessary voltage and current for variable load

Question 73

series vs parallel circuit

Answer 73

series: constant current parallel: voltage current