Transcript Chapter 6, Section 3

Series and Parallel Circuits: Lighten
Up
• LO
– Compare series and parallel
circuits and learn the
language of electricity.
• Do Now:
– Copy LO and SC on new
left side page
– WDYS/WDYT pg. 614
• SC
– Compare series and parallel
circuits
– Recognize generator output
limit
– Modify the Electron-Shuffle
model of electricity
• Agenda:
– Do Now
– Investigate Part A
• Electron Shuffle
– 3 bulbs in parallel
– Coulombs go to
• Light Bulb 1 if your bday is in Jan, Feb, Mar, Apr
• Light Bulb 2 if your bday is in May, June, July, August
• Light Bulb 3 if your bday is in Sept, Oct, Nov, Dec
• 1-volt battery=1 Joule per Coulomb
– Battery: “The battery Voltage is 1 Volt, which equals one
joule of energy for each coulomb”
– Coulomb: “One coulomb of energy receiving one joule of
energy”
– Light Bulb: “I just received 1 Joule of energy from that
coulomb”
• Pg. 615
– #4a, b
• Electron Shuffle
– 3 Volt battery
– 1 Amp current
• Electron Shuffle
– 1 Volt battery
– 2 Amp current
• Pg. 616
– #7 a-e
• LO
– Compare series and parallel
circuits and learn the
language of electricity.
• SC
– Compare series and parallel
circuits
– Recognize generator output
limit
– Modify the Electron-Shuffle
model of electricity
• Do Now:
– What happened to the
brightness of the bulbs
in a parallel circuit when
compared to the bulbs in
series circuit?
• Agenda:
– Do Now
– Investigate Part B
• #1-2 complete in groups, discussion
• #3-4 complete in groups, show teacher
• #5-6 complete in groups, show teacher,
discussion
• Series Circuit
• Total voltage of the battery
is divided equally between
all bulbs in the circuit.
• Coulombs of charge must
go through each bulb and
drop off joules of energy.
• If one bulb is removed, the
circuit is open and ALL the
bulbs will go out.
• 1 volt battery, each bulb
will receive 1/3
• Bulbs will appear dimmer
• Parallel Circuit
• Total voltage provided to
each bulb is equal to the
voltage of the battery.
• Each bulb has a complete
circuit from the battery to
the bulb and back to the
battery
• If one bulb is removed,
others will remain lit
• Bulbs will be equally bright.
• Battery will run out more
quickly
• Series example:
• 6 volt battery
• How many joules will
each bulb get?
• Parallel Example
• 6 volt battery
• How many joules will
each bulb get?
• What about the current
in a parallel circuit?
• Current (coulombs/sec) is
divided in a parallel circuit
• Example: If a parallel
circuit has a 3 amp current,
each bulb gets one amp of
current
• How much current would
each bulb get if it was a 9
amp circuit?
• Put it all together!
• 9 Volt battery with a 3
amp current
– Each bulb receives ____
joules of energy
– Each bulb receives ____
amps of current
• Put it all together!
• 9 Volt battery with a 3
amp current
– Each bulb receives __9__
joules of energy
– Each bulb receives __1__
amps of current
– One coulomb will pass
each resistor (bulb)
every second and drop 6
volts there.
• What is a resistor?
• A conductor that
controls the current in a
circuit.
• What is voltage drop?
• How many joules the
coulomb drops off at
each resistor
• 2 kinds of electric charges
– Positive (protons)
– Negative (electrons)
• Like charges (++ or - -) will repel
• Protons and electrons have opposite but equal
charges
– Protons (1+)
– Electrons (1-)
• Electrons move in circuits and carry the
electrical current delivering energy to the bulb
• Protons do not flow because they are locked
within atoms
• Standard “package” of electric charge is called a
Coulomb (C)=6.25 x 1018 electrons
– Approximately the charge of a bolt of lightning!
• Standard rate of flow through a circuit is an
ampere (A).
– # coulombs that pass through a point in one
second
• Resistance is the opposition to the flow of electric
charge
– Resistors are objects that oppose flow of electric charge
(light bulb)
– Example: High resistance-Tungsten filaments in light
bulbs glow as they “rob” energy from passing electrons,
causes the tungsten to get hot and glow=LIGHT!
– Example: Low resistance-copper wire, electrons transfer
little energy so we use copper to conduct electricity in
circuits
– Measured in Ohms (Ω)
– Was the steel wool high or low resistance? Why?
• Batteries or generators provide energy to the
electrons (coulombs)
• Energy given to each coulomb is measured in
Volts (V)
• What does it mean?
• How do you know?
• Why should you care?
• LO and SC reflection