Chapter 12

  1. Direct Current (DC)
    Definition: current in which charged particles (electrons) flow through a circuit in only one direction

    Extra Info: DC is found in batteries.

    Example: Cell phone, flashlight. (use batteries)
  2. Alternating Current (AC)
    Definition: current in which charged particles (electrons) move back and forth in a circuit

    Extra Info: AC does not have a net direction of flow (it is zero) because the amount of electrons that go one way is equal to the amount moving in the opposite direction, so they cancel each other out and leave zero.

    • Example: Refrigerator, dryer. (Plug into wall)
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  3. Transformer
    Definition: an electrical device that changes the size of the potential difference of an alternating current

    Extra Info: There are different types of transformers. Transformers that increase potential difference are called step-up transformers, while ones that decrease it are called step-down transformers.

    • Example:
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  4. Circuit Breaker
    Definition: a safety device that is in series with other circuits, which lead to appliances and outlets

    Extra Info: Circuit breakers work by being heated by the current, and if the current is too high, a part of the circuit breaker will snap from the heat, causing an open circuit.

    • Example:
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  5. Fuse
    Definition: a safety device mostly found in old buildings, and does a job similar to the circuit breaker using a similar method

    • Example:
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  6. Electrical Power
    Definition: the rate at which an appliance uses electrical energy

    Extra Info: The power rating of an appliance can be found on an EnerGuide label. It is used to find the energy used, and the cost of the energy.

    Example: The power rating of a typical toaster is 1.1kW.
  7. Watt (W)
    Definition: a unit of electrical power

    Extra Info: 1,000 watts is equal to one kilowatt.
  8. Kilowatt (kW)
    Definition: a practical unit of electrical power

    Extra Info: Kilowatt is often used over watt because most devices use large amounts of electricity, easier measured in kilowatts. 1,000 watts is equal to one kilowatt.
  9. Electrical Energy
    Definition: the energy that is used by an appliance at a given setting; determined by multiplying the power rating of an appliance (P) by the length of time it is used (t)
  10. Kilowatt-hour (kW.h)
    Definition: the practical unit of electrical energy

    Extra Info: Since most appliances are used for hours at a time, kW.s (kilowatt x seconds) is not as practical.
  11. EnerGuide Label
    Definition: a label that gives details about how much energy an appliance uses in one year of average use

    Extra Info: On EnerGuide labels, there is often a scale that shows how much energy the appliance uses compared to other appliances of the same type (the appliance that uses the least amount of energy would be better money wise).

    • Example:
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  12. Smart Meter
    Definition: a meter that records the total electrical energy used hour by hour and sends the information to the utility company automatically

    Extra Info: Ontario's goal was to replace all old meters with smart meters in every house by the year 2010.

    • Example:
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  13. Time of Use Pricing
    Definition: a system of pricing in which the cost of each kW.h of energy used is different at different times of the day

    Example: The cost for energy would be higher in the morning when most people heat their houses.
  14. Phantom Load
    Definition: the electricity that is consumed by appliances or devices when they are turned off

    Extra Info: This can be prevented by unplugging the appliance/device and turning off any power rods.
  15. Efficiency
    Definition: the ratio of useful energy output to total energy input, expressed as a percentage

    Extra Info: Percent efficiency can be found by dividing the useful energy output by the total energy input, then multiplying by 100.

    • Example: (1kW= 1kJ)
    • Percent efficiency=

    • useful energy output
    • total energy input        x100
    • 168 kJ
    • 198kJ    x100

    0.84848484  x100


    • Therefore, the percent efficiency is approximately 85%.
  16. Base Load
    Definition: the continuous minimum demand for electrical power

    Extra Info: The electrical energy generating method optimally suited for meeting the base load is nuclear energy, and hydroelectric energy.
  17. Hydroelectric Power Generation
    Definition: the generation of electrical power using a source of moving water

    • Example: Dam station, run-of-river station (both are used to turn turbines).
    • Dam station:
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    • Run-of-river station (diagram):
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  18. Intermediate Load
    Definition: a demand for electricity that is greater than the base load and is met by burning coal and natural gas
  19. Peak Load
    Definition: the greatest demand for electricity, which is met by using hydroelectric power and natural gas
  20. Renewable Energy Source
    Definition: a source of energy that can be replaced in a relatively short period of time

    Example: Hydroelectric energy, biomass energy (biofuels), wind energy, solar energy.
  21. Non-renewable Energy Source
    Definition: a source of energy that cannot be replaced as quickly as it is used

    Example: Fossil fuel energy, nuclear energy, coal energy.
  22. Solar Energy
    Definition: energy that is directly converted from the Sun into electricity

    • Extra Info: This is done using solar panels, and the photovoltaic effect.
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    • Solar panels are very expensive, but cost little to operate, but the cost of solar panels will decrease majorly in the coming decades.
  23. Photovoltaic Effect
    Definition: the generation of a direct current when certain materials are exposed to light (e.g. the material of solar panels)
  24. Biomass Energy
    Definition: energy that is generated from plant and animal matter

    Extra Info: This source of energy is renewable, and only releases as much carbon dioxide into the atmosphere as the plants absorbed during their growth ("carbon neutral"). A large supply of biomass is not always available for this however.
Card Set
Chapter 12
Chapter 12 Glossary Terms