Science 9- Unit D - Electrical Principles and Technologies
Brushes
Mechanisms that make electrical contact with the moving commutator in motor.
Multimeters
Meter that can measure voltage, current, or resistance in a circuit
Ammeters
Meter used to measure electrical current in amperes (amps)
Microcircuits/Integrated Circuits
Miniature electronic circuits, esp. ones in which a number of permanently connected components are contained in one small chip of semiconducting material.
Binary Numbers
Number having two as its base so only having ones and zeros.
Biomass
Organic Matter, such as food or agricultural waste, used as an energy source.
Electrochemical Cell
Package of chemicals designed to produce small amounts of electricity; produces electricity from chemical reactions.
Proton
Positively charged particle in the nucleus of an atom
Secondary Cells
Rechargeable cell
Armature
Rotating shafts and coils in a motor or generator.
Circuit Breakers
Special wire that heats up and turns off switch when excess current flows through an electrical circuit.
Commutator
Split ring in a motor that breaks the flow of electricity for a moment and then reverses the connection of the coil.
Nuclear Fission
Splitting of atoms, which transforms them into lighter elements and releases large amounts of energy.
Electrical Current
Steady flow of charged particles.
Electrical Discharge
Sudden transfer of electrical charge from one object to another, indicated by a spark.
Dry Cells
The electricity producing cells that we use every day in flashlights and portable radios
Amperes (A)
The unit of electrical current
Fuses
Thin piece of metal that melts to break an electrical circuit when excess current flow occurs.
Voltage Drop
Voltage across a resistor or other device in a circuit.
Superconductors
a perfect conductor; substance with no resistance to flow
Renewable Resources
a resource such as coal or resource such as water or wind energy that is continually replenished and therefore can be used indefinitely
Short Circuit
accidental low-resistance connection between two points in a circuit, often causing excess current to flow.
Potential Difference
change in the potential energy of electric charge compared to its potential energy at a reference point.
Kilowatt Hour
commonly used unit of electrical energy, equal to a power consumption of 1000 W for one hour.
Rheostat
continuously variable resistor used to regulate electric current
Alternating Current
current that flows back and forth 60 time per second; this is the current used in homes.
Electrolysis
decomposition of a substance by an electric current
Resistor
device having resistance to the passage of electrical current, often used to control current in a circuit
Transformers
device that changes electricity at one voltage into electricity at a different voltage; a step-up transformer increases the voltage; a step down transformer decreases the voltage.
Geothermal Energy
energy derived from the internal heat of earth.
Fly Ash
fine airborne ash produced by burning coal or other solid fuels
Fossil Fuels
fuel formed form dead plants and animals; coal,oil, and natural gas.
Law of Conservation of Energy
fundamental principle that energy cannot be created or destroyed.
Electromagnetic Induction
generation of electric current in a conductor by a changing magnetic field.
Voltmeter
instrument used for measuring potential difference in volts.
Parallel Circuits
A closed circuit in which the current divides into two or more paths before recombining to complete the circuit.
Voltage
A measure of how much electrical energy a charged particle carries.
Transistors
A semiconductor device with three connections, capable of amplification in addition to rectification.
Battery
A set of cells connected together
Static Electricity
A stationary electric charge
Energy
Ability to do work.
Ion
An atom or group of atoms that has become electrically charged through the loss or gain of one or more electrons and has a negative or positive charge.
Rechargeable Cell
Cell that produces electricity by means of a chemical reaction that can be reversed by using an external source to run electricity back through the cell
Primary Cells
Cell that produces electricity by means of a chemical reaction that cannot be reversed
Series Circuit
Circuit in which there is only a single pathway for the current so the same current passes through all the components.
Electromagnet
Coil of insulated wire (usually wrapped around a soft iron core) that becomes a magnet when current flows through it.
Circuit
Complete path that charged particles flow through.
Charge Separation
Concentration of like charges in specific areas of a neutral object; for example, a negatively charged object brought close to a wall repels the electrons in the wall, leaving the area of the wall closest to the object positively charged.
Electrode
Conductor through which electric current enters or leaves a device or material
Galvanometers
Device for measuring and detecting small electric currents
Load
Device in a circuit that converts electrical energy to another form of energy (eg. a light bulb)
Schematic
Diagram using standardized symbols to show the components and connections in a circuit.
Wet Cells
Electrochemical primary cell having a liquid electrolyte
Electrical Energy
Energy of charged particles; transferred when electrons travel from place to place.
Chemical Energy
Energy stored and released when chemicals react; a form of potential or stored energy.
Millivoltmeters
Instrument used to measure small voltages.
Electron
Invisible negatively charged particle that orbits the nucleus of an atom.
Ohm's Law
Law stating that, as long as the temperature remains constant, the resistance of a conductor remains constant, and the current is directly proportional to the voltage applied; R = V/I or I = V/R or V = IR
Electrolyte
Liquid or paste that conducts electricity because it contains ions
Turbine
Machine that uses the flow of a fluid such as: steam, water or air to rotate a shaft.
Neutral
(in chemistry) pH of 7; a neutral substance is neither an acid nor a base.
Resistance
measure of how difficult it is for electrons to flow through a substance; unit of measure is ohm
Nonrenewable Resource
natural gas that cannot be replenished
Fuel Cells
primary cells that generates electricity directly from a chemical reaction with a fuel.
Power
rate at which a device converts energy.
Variable Resistor
resistor whose resistance can be changed by adjusting the portion of the resistor the current travels through
Electrochemistry
study of chemical reactions involving electricity
Insulators
substance that strongly resists the flow of electricity
Watt
the unit of power, equal to one joule per second.
Ohms
the unit of resistance
Volt
the unit of voltage
Electroplating
use of electricity to coat a thin layer of metal onto an object
Sustainability
use of resources at a rate that can be maintained indefinitely without depleting the resources or harming the environment.