Download Types of Electric Circuits Series Circuit Mini-Lab

Schematic diagram:
• A diagram of an electric circuit
• Straight Lines Only!
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THIS
Schematic Diagrams Symbols:
Battery
Open Switch
Resistor
Closed Switch
Bulb
Types of Electric Circuits
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2 types of electric circuits:
Series Circuits
and
Parallel Circuits
More than one
path possible
for electrons to
flow
A single
path for
electrons to
flow
Series Circuit
Mini-Lab
Make a circuit with two bulbs in series.
Total resistance = sum of the
individual resistances (light
bulbs) on the circuit path.
If one bulb burns out,
the whole strand of lights won’t work!
Done? Have a seat and continue to
work on the reading assignment.
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Mini-Lab
Add a switch to your last circuit that can
turn both bulbs on and off.
Done? Have a seat and continue to
work on the reading assignment.
Parallel Circuit
Mini-Lab
Make a circuit with two bulbs in parallel.
On a warm up paper, draw a schematic of
this circuit.
Done? Have a seat and continue to
work on the reading assignment.
Mini-Lab
Add a switch to your last circuit that can
turn one bulb on and off without
affecting the other.
Done? Have a seat and continue to
work on the reading assignment.
Mini-Lab
END
Add another switch to your last circuit so
that the other bulb can be turned on and
off also, without affecting the other. s
Done? Have a seat and continue to
work on the reading assignment.
2
An Analogy for a Circuit:
Voltage, Current and
Resistance
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VOLTAGE
(V)
is
ELECTRICAL POTENTIAL ENERGY
and is measured in
VOLTS (V)
What is Voltage?
Voltage is like “pressure” that
pushes charge through the circuit.
Voltage is a kind of
potential energy
(stored energy)
The metric unit used to measure voltage is volt (V).
Voltage can describe the
energy stored in batteries:
Low Voltage
(Low Potential Difference)
High Voltage
(High Potential Difference)
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Anatomy of a Battery
About Batteries:
Positive Terminal
Zinc Anode (-)
How does a battery work?
Electrons collect on the negative
terminal of the battery. If you connect a
Graphite Cathode (+)
wire between the negative and positive
terminals, the electrons will flow from
Chemical Paste
(makes the electrons)
the negative to the positive terminal
as fast as they can.
Negative Terminal
About Batteries:
Where does a battery get its electrons?
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CURRENT
(I)
Inside the battery itself, a chemical
reaction produces the electrons.
The speed of electron production
by this chemical reaction controls how
many electrons can flow between the
terminals.
CURRENT (I)
measures the flow of charge
1 AMP of Current
means
6,250,000,000,000,000,000
electrons per second!!
ELECTRIC CURRENT is
the FLOW of electrons,
measured in
AMPERES (A)
What is Current (I)?
Current is the flow of electrons
through the circuit.
Current is measured in electrons
per second, called amperes.
The metric unit used to measured current is amperes (A)
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What’s difference between…
Current I
Voltage V
(in Amperes)
(in Volts)
RESISTANCE
R
you could say that…
Volts
measure the
pressure in
the hose.
ELECTRICAL RESISTANCE
slows down the current
and is measured in
OHMS ()
Amps
measure how
much water
comes out of a
hose per second.
What is Resistance?
Resistance
Resistance controls the amount of
current in a circuit.
Think of water
flowing through
a pipe. A narrow
pipe has more
resistance
because of it
slows the flow of
water through
the pipe.
The greater the resistance, the
less current gets through.
•The
metric unit for measuring resistance is the Ohm (
)
Conductors vs. Insulators
•Conductors – material
through which electric
current flows easily;
they have low
resistance.
Insulators – materials
through which electric
current cannot move;
they are resistors.
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Ohm’s Law
V = IR
Relates:
Voltage (V) in volts (V)
V
I R
V = IR
Current (I) in amperes (A)
I = V/R
Resistance (R) in ohms ()
R = V/I
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Examples
Problem 1: A stove is connected to a 180-V outlet. If
the heating element has a resistance of 18 calculate
the current flowing through it.
Formula:
I=V
R
I = 180 V

I = 10 A
Given:
V = 180 V
I=?
R = 18 
Therefore, the current flowing through the stove is 10 A
Examples
Problem 3: If the resistance of fridge is 130 and the
current is 0.845 A, what is the voltage?
Given:
V=?
I = 0.845 A
R = 130 
Formula:
V=IxR
V = 0.845 A x 130 
V = 109.85 V
Examples
Problem 2: In order to operate a hairdryer, the current
required is 2.5 A. What is its resistance if the voltage
supplied is 120 V?
Formula:
Given:
V = 120 V
I = 2.5 A
R=?
R=V
I
R = 120 V
2.5 A
R = 48 
Therefore, the resistance of the hairdryer is 48 
Question # 1
A light bulb supplied
with a voltage of 36 V
has a 6 A current
flowing through it.
Calculate the
resistance of the light
bulb.
Therefore, the voltage of the fridge is 109.85 V
Question #2
Electric Power (P)
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A light bulb has a
resistance of 3 . What
is the current in the
light bulb when a
voltage of 12 V is
supplied?
POWER IS MEASURED
IN WATTS
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Electric Power Formula
P=I/V
Relates:
I
P V
Voltage (V) in volts (V)
P=I/V
Current (I) in amperes (A)
V=I/P
Power (P) in watts (W)
I = PV
A schematic diagram is a special diagram that
describes an electric circuit, using certain symbols
to represent different devices in the circuit.
This meter measures the amount of electric work
done in the circuits, usually over a time period of a
month. The work is measured in kWhr.
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THIS
Schematic Diagrams Symbols:
Battery
Open Switch
Resistor
Closed Switch
Bulb
Types of Electric Circuits
COPY
THIS
Series Circuit
2 types of electric circuits:
Series Circuits
A single path
for electrons to
flow
and
Parallel Circuits
More than one
path possible for
electrons to flow
Total resistance = sum of the
individual resistances (light
bulbs) on the circuit path.
If one bulb burns out,
the whole strand of lights won’t work!
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Parallel Circuit
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