Transcript Electric Current and Electric Circuits

Electric Current
Electrical current is the flow of electrons. Unlike static electricity,
charges are in motion.
Two types of Current
I. Direct current (DC) - flow of electrons in one direction.
car battery, flashlight batteries, photovoltaic (solar) cell
II. Alternating current (AC) - flow of electrons back and forth along
a path.
electric generator
Electric Current
CURRENT (I) – flow of electrons along a conductor
unit: ampere (amp)
1 ampere = 1 coulomb/1sec
RESISTANCE ( R ) – opposition to the flow of electrons. Electrons do work
and lose energy in the form of heat.
unit: ohm (W)
Jsec/coulomb2
VOLTAGE ( V ) Potential Difference - energy available to move electrons
from objects of high potential to objects of low potential energy. measures
amount of work electrons can do if they move between two points.
unit: volt (V)
1 volt = 1Joule/1 coulomb
High voltage greater potential to do work.
Low voltage less potential to do work.
e'
e'
e'
High potential energy
charged
Low potential energy
uncharged
Electric Current
OHM‘S LAW - current is dependent on voltage and resistance.
It is directly proportional to voltage and inversely proportional to resistance.
current = voltage
resistance
I = V
R
units: amps = volts
ohms
The greater the voltage, the greater the current
The lower the voltage, the lower the current
The lower the resistance, the greater the current
The greater the resistance, the lower the current
Electric Circuits
Circuit – path, or loop, formed by a conductor that allows electrons to flow.
SERIES CIRCUIT - circuit where current travels through only one loop
PARALLEL CIRCUIT - circuit consisting of several smaller circuits
connected together
Electric Circuits
Circuit – path, or loop, formed by a conductor for electrons to flow.
SYMBOLS -
conductor
switch (open)
switch (closed)
power source
(battery)
flow
light bulb
resistor
Fuse - metal in a circuit which melts when current is too high
Circuit breaker - metal in a circuit which bends when current is too high
http://phet.colorado.edu/en/simulation/circuit
-construction-kit-dc