Series versus Parallel Circuits The Ultimate Battle!

Series versus Parallel CircuitsSeries versus Parallel Circuits

The Ultimate Battle!The Ultimate Battle!

KEY POINTSKEY POINTSNEW VOCABULARY:NEW VOCABULARY:

–ResistanceResistance

–VoltageVoltage

–Ohm’s LawOhm’s Law

RESISTANCERESISTANCE

RESISTANCE = the tendency for a RESISTANCE = the tendency for a material to oppose the flow of electrons, material to oppose the flow of electrons, changing electrical energy into thermal changing electrical energy into thermal energy and light.energy and light.

All materials have some electrical All materials have some electrical resistance.resistance.

Resistance is measured in Ohms (Resistance is measured in Ohms (

RESISTANCERESISTANCE

Examples:Examples:1)1) LightbulbLightbulb

-Electrons flow through the filament of the lightbulb and -Electrons flow through the filament of the lightbulb and bump into the metal atoms that make up the bump into the metal atoms that make up the filament.filament.

-Some of the electrical energy from the bumps turns -Some of the electrical energy from the bumps turns into thermal energy.into thermal energy.

-Eventually the metal filament gets hot enough to glow, -Eventually the metal filament gets hot enough to glow, making the lightbulb light up!making the lightbulb light up!

-Electric current loses energy as it moves through the -Electric current loses energy as it moves through the filament because the filament tries to stop the flow filament because the filament tries to stop the flow of electrons (HIGH RESISTANCE!!!)of electrons (HIGH RESISTANCE!!!)

RESISTANCERESISTANCE

Examples:Examples:2) Copper wiring2) Copper wiring

-Excellent to use in houses because it -Excellent to use in houses because it has low resistance to the flow of electronshas low resistance to the flow of electrons

-Less electrical energy is converted to -Less electrical energy is converted to thermal energy so there is more electrical thermal energy so there is more electrical energy to power the house!energy to power the house!

(LOW RESISTANCE)(LOW RESISTANCE)

SAVE ENERGY! USE COPPER WIRES! SAVE ENERGY! USE COPPER WIRES!

Factors that affect resistance…Factors that affect resistance…

SIZE OF WIRESIZE OF WIRE– Electrons move more efficiently through thick Electrons move more efficiently through thick

wireswires

(Thin wires have more resistance!)(Thin wires have more resistance!)

-The longer the wire the higher the resistance!-The longer the wire the higher the resistance!

TEMPERATURETEMPERATURE-High temperatures are also linked with high -High temperatures are also linked with high

resistanceresistance

VOLTAGEVOLTAGE

Voltage is like an electrical pressure that Voltage is like an electrical pressure that pushes charges from high to low levels!pushes charges from high to low levels!

Voltage is measured in volts (V)Voltage is measured in volts (V)

Just like water flows from high to low levels, electrical charges do

that too!

Ohm’s LawOhm’s Law

There is a relationship between current, There is a relationship between current, voltage, and resistance.voltage, and resistance.– Current = I and is measured in amps (A)Current = I and is measured in amps (A)– Voltage = V and is measured in volts (V)Voltage = V and is measured in volts (V)– Resistance = R and is measured in ohms (Resistance = R and is measured in ohms (

Current = Current = voltagevoltage I = V / RI = V / Rresistanceresistance

V = IRV = IR

KEY POINTSKEY POINTS

Anything that is plugged into an outlet requires electrical Anything that is plugged into an outlet requires electrical energy!energy!

That energy is moved around in That energy is moved around in CIRCUITSCIRCUITS! !

EX: Hair dryerEX: Hair dryer1. The dryer has to be plugged into the outlet to operate.1. The dryer has to be plugged into the outlet to operate.

2.2. A generator at the power plant produces a voltage difference A generator at the power plant produces a voltage difference across the outlet that makes charges move when the circuit is across the outlet that makes charges move when the circuit is complete.complete.

3.3. The dryer and the house have wires that carry the current.The dryer and the house have wires that carry the current.

4.4. The dryer turns the electrical energy into thermal and mechanical The dryer turns the electrical energy into thermal and mechanical energy.energy.

5.5. You break the path of current in the circuit when you turn off the You break the path of current in the circuit when you turn off the dryer or unplug it.dryer or unplug it.

The Snowman Robber!The Snowman Robber!

Types of Circuits!Types of Circuits!

Two types of Two types of circuits:circuits:

–SERIESSERIES

–PARALLELPARALLEL

SERIES CIRCUITSERIES CIRCUIT

Current flows through Current flows through ONEONE loop! loop!

The parts of a series circuit are wired one The parts of a series circuit are wired one after another.after another.

The amount of current and voltage are the The amount of current and voltage are the same through every part.same through every part.

When any part is disconnected, no current When any part is disconnected, no current flows and the entire circuit goes out!flows and the entire circuit goes out!

Also called an Also called an OPEN CIRCUITOPEN CIRCUIT!!

SERIES CIRCUITSERIES CIRCUIT

Examples: Examples:

–FlashlightsFlashlights

–Holiday lightsHoliday lights

THINK, PAIR, SHARE…THINK, PAIR, SHARE…

Where would a series circuit be Where would a series circuit be inconvenient? Why?inconvenient? Why?

SERIES CIRCUITSERIES CIRCUIT

SERIES CIRCUITSERIES CIRCUIT

SERIES CIRCUITSERIES CIRCUIT

PARALLEL CIRCUITSPARALLEL CIRCUITS

Parallel circuits have 2 or more branches Parallel circuits have 2 or more branches for current to move through.for current to move through.

The voltage is the same in each branch of The voltage is the same in each branch of the circuit, but more current flows through the circuit, but more current flows through branches that have lower resistance.branches that have lower resistance.

Advantages to Parallel Circuits…Advantages to Parallel Circuits…

When one part is disconnected, the current When one part is disconnected, the current still flows through the other branches.still flows through the other branches.

Houses, cars, and most electrical systems Houses, cars, and most electrical systems use parallel wiring.use parallel wiring.

THINK, PAIR, SHARE…THINK, PAIR, SHARE…

Why do you think houses use parallel Why do you think houses use parallel circuits?circuits?

Parallel CircuitParallel CircuitIn a parallel circuit the In a parallel circuit the current flow splits up current flow splits up and goes to different and goes to different parts of the circuit. If parts of the circuit. If one bulb or appliance one bulb or appliance goes out, the rest stay goes out, the rest stay on. All bulbs are on. All bulbs are equally bright.equally bright.

PARALLEL CIRCUITSPARALLEL CIRCUITS

PARALLEL CIRCUITSPARALLEL CIRCUITS

COMPARE/CONTRASTCOMPARE/CONTRASTSERIESSERIES– One loop of currentOne loop of current– Same voltage Same voltage

everywhereeverywhere– Same current Same current

everywhereeverywhere– If one part is If one part is

disconnected the disconnected the whole circuit goes outwhole circuit goes out

– Used in lightbulbs!Used in lightbulbs!

PARALLELPARALLEL– 2 or more branches of 2 or more branches of

currentcurrent– Same voltage Same voltage

everywhereeverywhere– Current changes based Current changes based

on resistanceon resistance– If one part is If one part is

disconnected, the circuit disconnected, the circuit still carries electricity to still carries electricity to the other branchesthe other branches

– Used in houses and cars!Used in houses and cars!

COMPARE/CONTRASTCOMPARE/CONTRAST