52 terms

Sci 9: Unit D - Electrical principles and Technology

AB Grade 9 Electricity Principles
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Terms in this set (...)

battery
A device that provides electrical energy from chemical energy
conductor
A material that allows heat or electricity to pass through it.
current
A flow of electric charge.
electron
Negatively charged particle
energy
Ability to do work
generator
A machine that converts mechanical energy into electrical energy
insulator
A material that does not allow heat or electrons to move through it easily.
Ohm's Law
The relationship of voltage, current, and resistance
voltage
The potential difference measured in volts. Related to the force that causes electrons to flow in a circuit.
ion
An atom or group of atoms that has a positive or negative charge.
electric force
The attraction or repulsion between electric charges
Magnet
Provides magnetic field
Electric current
The rate of flow of electric charges through a material
circuit
Closed conducting loop through which electric current can flow.
Resistance
Measure of how difficult it is for electrons to flow through a material; unit is ohm
Electric Power
The rate at which electrical energy is converted into other forms of energy; measured in kWh
Motor
A device that converts electrical energy to mechanical energy
Electrical energy
Energy caused by the movement of electrons.
Transformer
A device that increases or decreases voltage in power transmission
Circuit breaker
A device that is used to protect appliances in a circuit from a current surge
Fuse
A device used to protect an appliance from power surge
Transistor
A device that acts as a switch in a circuit board or microprocessor
Conservation of Energy
Energy cannot be destroyed or created but can be transferred from one form into another
laws of electric charges
1.) unlike charges attract
2.) like charges repel
3.) charged objects attract neutral objects
Static electricity
Charges on two objects rubbing together
series circuit
An electric circuit with only one path through which current can flow
dry cell
an electrochemical cell in which the electrolyte is a paste
direct current
Current that flows through a conductor in one direction only.
thermocouple
a device that converts thermal energy into electrical energy
ammeter
connected in series to measure current in a circuit
voltmeter
connected in parallel to measure voltage across a device
power
the rate at which energy is used - measured in Watts
parallel circuit
A circuit that contains more than one path for current flow.
electromagnet
a soft iron core wrapped with a current carrying coil that is magnetized when current passes through the coil
thermistor
A resistor that changes its resistance with a change of temperature.
watt
A measure of power equal to one joule of work per second.
electrode
a conductor in a circuit that carries electrons to or from a substance other than a metal
alternating current
A flow of electric charge that regularly reverses its direction.
rheostat
A device which can vary the resistance without opening the circuit - the electrical device can continue to work even as the resistance is altered
wet cell
Cell containing an electrolyte which is liquid, usually an acid
secondary cell
Cell created by using chemical reactions that can be reversed, so the cell is rechargeable.
LED
Light Emitting Diodes - efficient light bulbs that work when current flows in one direction
Piezoelectric Effect
Flow of electrical current that results from compression of certain materials like quartz
Electric Charge
Positive and Negative charges of matter; measured in Coulombs
Semi Conductors
A material that conducts electricity or heat under certain conditions - used in microprocessors
Super Conductors
A material that offers zero resistance when cooled below a certain temperature
Armature
A loop or coil of wire that can rotate in a magnetic field
Commutator
Causes electric current to change direction in an electric motor
Grounding
Neutralizing any excess charge build up on an object by connection to earth with a conducting wire
Factors affecting resistance of a wire
1. Length
2. Cross section area
3. Temperature
4. Type of metal
Brushes
Provide electrical contact to the power supply in a motor or generator
DC Supply
DC source of electrical energy in a motor

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