Download Electric Current/Electrical Energy

Electric Current/Electrical Energy
Current
• The rate at which charges pass a given point.
The higher the current, the greater the
number of charges that pass the point each
second.
• Measured in Amperes (amps)
2 types of current
• Direct current – charges flow in one direction
(charges from batteries)
• Alternating current – charges continually shift
from flowing in one direction to flowing in the
reverse direction. (home outlets)
Voltage
• The potential difference between 2 points in a
circuit.
• Expressed in volts (v).
• (Basically, how much energy is needed to get
the charge through the wire)
• If an item doesn’t need a lot of electricity to
run, it’s low voltage. If it needs a lot, it’s high
voltage.
Resistance
• The opposition to the flow of electric charge.
• Resistance is expressed in Ohm’s.
• Electrical wiring is very low resistance. Light
bulbs, toaster wire is high resistance.
• The bigger the wire, the less resistance. The
colder the wire, the less resistance.
Superconductors
• Certain materials, that if cooled enough, will
have a resistance of 0 Ohms.
• Superconductors also repel magnets
Cells
• Change chemical or radiant energy into
electrical energy.
Contains a mixture of chemicals called an
electrolyte, which allow charges to flow.
• Also contains electrodes, which is the part of
the cell where charges enter and exit.
• There are 2 kinds of cells – wet cells and dry
cells.
Wet/Dry Cells
• Wet Cell Ex: Car battery
• Combine the use of acids as the electrolyte,
and metal connectors as electrodes.
• Dry Cell Ex: Batteries –
• The electrolytes are solid or pastelike
Thermocouples
• Converts thermal energy into electrical
energy.
• Thermocouples do not generate a lot of
energy
Photocells
• Converts light energy into electrical energy.
• When light shines on the photocell, electrons
gain energy to move between atoms. The
electrons move through a wire to provide
energy to power a device.
• Ex: Solar panel