Electricity 324 Flashcards
What is electricity?
Movement of electrons along a conductor.
Current is measured in
Amperes or AMPS
Volts are:
The measure of force moving electrons.
Current is:
The rate at which electrons flow. Measured in Amperes or AMPS
How do we produce electricity?
Friction (Static Electricity) Heat (Thermocouples) Light (Photoelectricity) Pressure (Piezoelectric Cells) Chemical Action (Batteries) Magnetism (Alternators/Generators)
What is an electron?
The smallest part of an atom, possessing a negative charge.
What is a conductor?
materials, usually metals, that have loosely held electrons in the outer orbit of their makeup.
What is an insulator?
Opposite of a conductor, does not have loosely held electrons in the outer orbit.
What is a circuit?
A path electricity can take;
always circular in nature between the area of negative and positive charge.
What is an AMP ?
RATE OF FLOW
Represents the current flow at a certain point.
FLOW
What is a VOLT?
The force that pushes electrons.
PRESSURE
What is resistance? How is it measured?
Electrical Friction, it is measured in OHMS.
What is a WATT?
What is the measurement of power .
VOLTS X AMPS = WATTS
pressure) (flow
Why do we use electricity the way we do?
Electricity allows light bulbs to burn.
It allows cars to have generators and electricity like batteries.
Causes chemicals to recharge and hold energy.
How many WATTS are in 1 hp.
746 WATTS = 1 HP
What are the two types of Current
Direct Current
Alternating Current
Direct Current (DC)
How does it flow? How is it generated? How far does it travel? What is it usually used for? Name something DC is used in and what kind of energy?
Flows in one direction.
Generated by moving a coil of wire in a magnetic field.
Doesn’t go very far.
Used for shorter circuits.
Most batteries use DC, which is chemical energy.
Alternating Current (AC)
How does it flow? How far does it travel? What is the rate of flow for a standard household? Why is it economical? How is it generated? What is the phase? What do the hertz measure?
It flows in both directions, constantly changing.
Efficient for long distance flow.
60hz rate for the average household.
It’s cheaper and more efficient than DC.
Generated by moving coil of wire in a magnetic field.
400hz 115 Volts
Hertz is cycles per second.
What three things does a simple circuit contain?
How is it controlled?
What are some examples of consuming devices you could use on this?
A circuit with a power supply, switch, and consuming device.
Controlled by opening and closing the switch/circuit.
Lightbulb, motor, heater.
What are switches used for?
What does that do?
What are different types?
Used to open or close a circuit.
Used to activate electrical devices.
Mechanical Vs. Automatic
Wet Cell Batteries can/can not be recharged?
Can be recharged
What kind of alternator do we have in the C172?
28v 60amp
Alternators spin a ___________ inside a __________, and requires/does not require brushes to pick up current.
More/Not Efficient and operate on a _____ RPM and are_______ in weight.
Alternators spin an electromagnet inside a coil. Requires no brushes to pick up current.
More efficient and operate on a lower RPM and are lighter in weight.
Generators spin a ___________ inside a __________, and requires/does not require brushes to pick up current.
More/Not Efficient and operate on a _____ RPM and are_______ in weight.
Generators spin a coil inside a heavy magnet and require brushes to pick up current.
Not as efficient as an alternator.
If an ammeter is reading -10 the battery is providing ______ power than the _______
More power than the battery.
What is thermal runaway?
Thermal runaway refers to a situation where an increase in temperature changes the conditions in a way that causes a further increase in temperature, often leading to a destructive result. It is a kind of uncontrolled positive feedback.
What does the ammeter indicate?
How do you know when you have an alternator failure?
Indicates rate of charge, or discharge of battery.
Loss of alternator indicated by a negative reading.
What does load meter indicate?
How do you know you have an alternator failure ?
Load meter indicates amount of total electrical load in amps that’s placed on the alternator.
Load meter indicates 0 you have an alternator failure.
What are busses?
How do they connect?
Power distribution points with clusters of electronic components connected to one terminal.
Usually a metal strip connects them.
Preflight for the electrical system: (3)
- Check alternator, belt, tight good shape.
- Use battery cart for cold winter starts
- Check operation before takeoff
