Download UNIT SUMMARY: ELECTRICAL PRINCIPLES AND TECHNOLOGIES

UNIT SUMMARY: ELECTRICAL PRINCIPLES AND TECHNOLOGIES
Key Concepts
1.0
• electric charge and current
• circuits
• electrical energy storage
• energy transmission
• measures and units of
electrical energy
2.0
• electric current
• circuits
• energy transmission
• measures and units of
electrical energy
• electrical resistance and
Ohm's law
3.0
• forms of energy
• energy transformation
• generation of electrical
energy
• energy transmission
• measures and units of
electrical energy
4.0
• energy transformation
• energy transmission
• generation of electrical energy
• energy storage
• renewable and nonrenewable
energy
Section Summaries
1.0 Electrical energy can be transferred and stored.
•There are two types of electricity: static and current. Static is electrically charged particles at
rest. Current is flowing electrically charged particles.
• Voltage is a measure of how much electrical energy each charged particle carries. Current is
the rate at which charged particles flow.
• Electricity can be dangerous, so safety should always be a concern.
• Electricity can be produced through chemical reactions and stored in different types of cells.
Cells can be combined to form batteries.
2.0 Technologies can be used to transfer and control electrical energy.
• Different substances provide various levels of resistance to electric current. Electricity flows
more easily in conductors than in insulators.
• The amount of electrical resistance is measured in ohms. Voltage is measured in volts.
Current is measured in amperes.
• Ohm's law states that the current flowing through a conductor is proportional to the voltage
applied to it.
• Meters are used to measure electricity. Voltmeters measure voltage. Ammeters measure
current. Ohmmeters measure resistance. Multimeters measure all three.
• Series circuits provide a single pathway for current. Parallel circuits provide multiple pathways
for current.
3.0 Devices and systems convert energy with varying efficiencies.
• Energy exists in different forms, such as chemical, thermal, mechanical, and electrical energy.
• Energy can be transformed from one form into another. For example, a thermocouple can
change thermal energy into electrical energy.
• Electric motors transform electrical energy to mechanical energy.
• Power is the rate at which a device converts energy. It is calculated by multiplying current by
voltage. Energy is calculated by multiplying power by time.
• Input energy and usable output energy can be compared to determine the efficiency of an
energy-converting device.
• Reducing the amount of energy wasted by devices that convert energy increases their
efficiency.
4.0 The use of electrical energy affects society and the environment.
• A variety of alternative energy sources can be used to generate electrical energy. These
include fossil fuels, nuclear energy, geothermal energy, biomass, hydro-electricity, tides, wind
power, and solar energy.
• Energy sources are either renewable or nonrenewable.
• Electrical generation can produce by-products and effects that harm the environment.
• Energy and nonrenewable resources can be conserved through choices that reduce
consumption.
• Sustainability means using resources at a rate that can be maintained indefinitely.
Unit D: Electrical Principles and Technologies