Download circuits 1.notebook

circuits 1.notebook
May 15, 2013
Electricity
current
voltage
resistance
power
amps
volts
watts
ohms
direct current
alternating current
May 15­10:39 AM
Electric Force and Charge
Electrical Force - like charges repel and oppositely charged
particles attract
Protons are
positive
Normally
there is an
equal
number of
protons and
electrons
making the
atom
neutral
Neutrons are
neutral
Electrons are
negative
May 15­10:45 AM
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circuits 1.notebook
May 15, 2013
Ions are charged particles
Positive ions have lost one or more electrons
Negative ions have gained one or more electrons
Polarization - the process of separating
opposite charges within an object
May 15­10:48 AM
Coulomb's Law
F=k (q1q2) ÷ (d2)
F- electrical force
d - distance
q - charge of each particle
k - 9,000,000,000 Nm/C2, proportionality constant
Electrical Field (E)- energetic aura that extends through space and
has both magnitude and direction
E- F/q
May 15­10:52 AM
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circuits 1.notebook
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Electrical Field Lines - visually show the direction and magnitude of
the electrical field
- always point away from the positive toward the negative
May 15­11:00 AM
Electrical Potential Energy- energy possessed by the charged
particle due to its position
Volts - unit of measurement of electric potential (voltage)
1V = 1 J / 1 coulomb
Electric potential - concept of energy per charge
May 15­11:04 AM
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circuits 1.notebook
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Voltage Sources
potential difference- charge flows from highest potential to
the lowest potential
There must be a potential difference for current to flow!
Chemical batteries and generators are electric pumps that can
maintain an electric flow or charge
Electric Current- the flow of charged particles
ampere- units of current flow (amp, A) - amount of 1 coulomb
charge in 1 second
May 15­11:06 AM
Conductors- many free electrons
Insulators - few or no free electrons, electrons are strongly
attached to atoms
Semiconductors- neither good conductors nor good insulators
Doping- process of providing free electrons by introducing small
amounts of another element
May 15­11:12 AM
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circuits 1.notebook
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Direct Current- flows in one direction
Alternating current- flows one way for a short time and back the
opposite direction
Electrical Resistance - Property of a material that resists flow of
current
Ohms- unit of resistance
resistance of wire- due to the diameter, length, material and
temperature
Ohms- unit of resistance, Ω
May 15­11:14 AM
Ohm's Law
amount of current is directly
proportional to voltage and
indirectly proportional to current
I= V/R
V
I- current (A)
V- voltage (v)
R- resistance (Ω)
When resistance goes up, current
decreases.
I
R
When Voltage goes up, current
increases
May 15­12:16 PM
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circuits 1.notebook
May 15, 2013
Circuit- any path in which electrons flow
series - a circuit in which there is only one path that the
electrons can travel
****a break in the series circuit causes all current to stop****
parallel- the devices are connected to the same two points of
an electrical circuit providing more than one path for current to
flow
*** a break in any one path in a parallel circuit does not interrupt
flow in the other paths****
May 15­12:27 PM
Electric Power
rate at which electric energy is converted to another form
Power = current x voltage= P = IV
P
Watt - unit of electric power
I
V
Kilowatt - 1000 watts of electric power
Kilowatt-hour - how many kilowatts are used in an hour
To find cost: kilowatts x time used x cost of kilowatt-hour - ($)
May 15­12:33 PM
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circuits 1.notebook
May 15, 2013
Magnetic Force
similar to electrical forces, in that magnets attract and repel
without touching
electric charges can be isolated and magnetic poles cannot
all magnets have both a North and South pole
Like poles repel; opposite poles attract.
Pole- dense regions of force concentrated at the ends. Each
time you break a magnet, it has a North and South pole.
no matter how small a magnet is when you break it, there will
always be two opposite poles
May 15­12:40 PM
Magnetic Field
energetic aura that extends through space
the shape of the field lines is revealed by magnetic field
lines- strength is greater at the poles
produced by moving electric charges due to the constant
spinning motion of electrons
every spinning electron is a tiny magnet- electrons spinning in
the same direction create a strong magnet, electrons spinning
opposite cancel each other out
Most common magnets are made from alloys containing iron,
nickel, cobalt and aluminum.
there is a magnetic field that surrounds all current carrying wire
May 15­12:43 PM
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circuits 1.notebook
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2Ω
6v
May 15­12:00 PM
2Ω
2Ω
2Ω
6v
May 15­1:36 PM
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circuits 1.notebook
May 15, 2013
2Ω
2Ω
2Ω
6v
May 15­12:32 PM
3Ω
3Ω
3Ω
6v
May 15­1:45 PM
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circuits 1.notebook
May 15, 2013
3Ω
3Ω
3Ω
6v
May 15­1:40 PM
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