Basic Electricity
What is an electron?
A negatively charged particle that is not considered in determining the weight of an atom
What is a neutron?
A neutrally charged particle that's located in the nucleus
What is the electron current theory?
An abundance of electrons flow out of the negative source to an area that lacks electrons or the positive source
What are the two competing schools of thought and analytically practices regarding the flow of electricity?
Conventional current theory and the electron current theory
What does DC stand for?
Direct current
What is dynamic electricity?
Electrons in motion
What is one of the most frequent causes of damage to a solid state component or integrated circuits?
Electrostatic discharge
The ability to do work
Energy
How is the schematic representation of conductors shown?
Generally as a solid line
What symbol represents resistance in ohm's law formula?
Greek letter omega
Electromagnetism was discovered by who?
Hans Christian Oersted
What is the formula for current?
I=Q/t
What is the left hand rule?
If the conductor is grasped in the left hand, with the thumb pointing in the direction of current flow, the fingers will be wrapped around the conductor in the same direction as the lines of the magnetic field
Glass and plastic are examples of what?
Insulators
The process by which an atom loses or gains electrons
Ionization
The property of an object that attracts certain metallic substances
Magnetism
What is the unit measurement for resistance?
Ohms
What are free electrons?
Outermost electrons that can be easily dislodged from the atom. They can travel from atom to atom becoming current in an electrical circuit.
What type of variable resistor is controlled by light intensity?
Photoconductive cells
_____ in sunlight are taken in by the solar panels, where they are then absorbed by semiconducting materials
Photons
Rate of energy consumption or conversion within that system. The amount of energy used or converted in a given amount of time
Power
What are the four most common ways to produce electrical energy?
Pressure, chemical, thermal, and light
What is the formula for resistance?
R=E/I
Material that falls in between the characteristics of conductors and insulators
Semiconductors
What is caused when non-conductive materials such as rubber, plastic, or glass are rubbed together, causing a transfer of electrons?
Static Electricity
Define Ohm's Law
The law that explains the relationship between the flow of electrons (current), electrical pressure (voltage), and the opposition to flow (resistance). The amount of current flowing in a circuit is directly proportional to the circuit voltage and inversely proportional to the circuit resistance
What is a thermal source?
The most common source of thermal electricity found in the aviation industry comes from thermocouples. Thermocouples are pairs of dissimilar metal wires joined at least at one end, which generate a voltage between the two wires that is proportional to the temperature at the junction
What type of variable resistor is temperature sensitive?
Thermistors
What four factors affect resistance?
Type of Conductor material Length Cross-sectional area Temperature
What type of resistor is constructed so that the resistive value can be changed and this adjustment can be manual or automatic?
Variable resistors
What type of resistor typically control large amounts of current and have high power ratings?
Wire-wound
What is a proton?
a Positively charged particle that's located in the nucleus
What is a compound?
a compound is a chemical combination of two or more elements
What is the unit of energy?
a joule
What makes a carbon composition resistor?
a mixture of finely grouped carbon/graphite, an insulation material, and a substance for binding
What is pressure source?
a result of the application of mechanical pressure on a dielectric or nonconducting crystal.
What is an element?
a substance that cannot be reduced to a simpler form by chemical means
What is a rheostat?
a variable resistor used to vary the amount of current flowing in a circuit
What is energy level?
amount of energy an electron requires to stay in orbits.
Electrons in motion make up what?
an electric current
The imbalance of charges between the two materials mean that the object will exhibit an _____ or ____ force
attractive or repulsive
What is an atom?
basic building block of all matter. Made up of a proton, neutron, electron, and nucleus
The strength of the magnetic field of the electromagnet can be increased how?
by either increasing the flow of current, the number of loops in the wire, and the type of metal core
We can demonstrate the characteristics of magnetic flux by what method?
by tracing the flux patterns of two bar magnets with like poles together
What is a chemical source?
chemical energy can be converted into electricity; the most common form of this is the battery. A primary battery produces electricity using two different metals in a chemical solution, where a chemical reaction between the metals and the chemicals frees more electrons in one metal than in the other
What is an electron shell?
closely spaced energy levels are grouped into shells. The first shell can contain 2 electrons; the second can contain 8; the third, 18; and so on until the seventh shell
Materials that offer low resistance to current flow
conductor
Elements such as gold, copper, and silver possess many free electrons and make good ______
conductors
The best ______ are materials which possess a large number of free electrons
conductors
What is a potentiometer?
considered to be a three terminal device
The two fundamental properties of _____ and ____ are related by a third property known as resistance
current and voltage
What is the conventional current theory?
developed by Ben Franklin who reasoned that current flowed out of a positive source into a negative source
What's it called when current flows in one direction?
direct current (DC)
If the magnet is suspended to swing freely, it will align itself with the _____ _____ ____
earth's magnetic poles
A field of force that exists around a charged body
electrostatic field
What does the 1st digit in a color band mean?
first digit in the numerical resistance value
Most objects become charged with static electricity by means of what?
fricition
How are voltmeter connected?
in parallel with a circuit
materials that offer a high resistance to current flow
insulator
What is the resistor color code?
it's made up a group of colors, numbers, and tolerance values. Each color is represented by a number, and in most cases, by a tolerance value
An invisible but always present field that surrounds magnets and exists between the poles
magnetic fields
What does the 4th digit in a color band mean?
multiplier for percentages of tolerance
What are two types of magnets?
natural or artificial
What does the 3rd digit in a color band mean?
number of zeros to be added to the 2 digits from the first two bands
Mega (M) means
one million
Kilo (k) means
one thousand
Micro (u) means
one-millionth
Milli (m) means
one-thousandth
What is another name for artificial magnets?
permanent magnets
A _______ ____ is a device that converts light energy into electricity.
photovoltaic cell
Pressure source is commonly known as what?
piezoelectric
What are the control properties that resistors are constructed and sized for?
resistance value, the precision of the resistance value, and the ability to dissipate heat.
ability of a magnet to hold magnetism is what?
retentivity
A ____ is a variable resistor used to vary the amount of current flowing through a circuit
rheostat
What are the two basic types of manual adjusters?
rheostat and potentiometer
What does the 2nd digit in a color band mean?
second digit of ohmic value
What is a molecule?
smallest particle of matter that can exist and still retain it's identity
There is no known insulator for magnetic flux, but instruments can be surrounded by a path of ____ ____ and the lines of force will take the easier path through
soft iron
What is Kirchhoff's Voltage Law?
states that the algebraic sum of all voltages around a closed path or loop is zero. The sum of all the voltage drops equals the total source voltage
A buildup charge on the surface of an object
static electricity
What special alloys are permanent magnets made of?
strontium and iron
The polarity of the electromagnet is determined by what?
the left-hand rule
The actual value of a resistor is known as what?
the tolerance of the resistor
What uses the same type of meter movement as the ammeter but employs a different circuit external to the meter movement?
the voltmeter
A______ is a variable resistor that works based on a negative temperature coefficient
thermistors
What is the general use of a resistor in a circuit?
to limit the amount of the current flow
What is the basic idea of a multirange ammeter?
to make the meter usable over a wide range of voltages
What is the function of a ohmmeter?
to measure resistance
The percentage variation between the marked value of resistance and the actual value of a resistor
tolerance of a resistor
A unit of energy can be called a ______ or more recognizable from the electric bill, a _____
watt-second (Ws) or kilowatt-hour (kWh)
What is it called when the ohmmeter leads are open, and the meter is at a full scale deflection indication an infinite resistance or open circuit?
zero adjustment