Download Types of Circuits

Name: _____________________
Unit 9:4
Types of Circuits
Period: _____________________
Wires and Voltage
Since wires are conductors,
they have no resistance,
so they have no
voltage difference.
Current joins
Junction
6A
12V 12V 12V
Current can split
apart or join together.
wires don’t change voltage at all.
Series circuits have all only
one path for the electricity to flow.
There are no junctions.
IT
IT
Junction
Current splits
Total current in and out
of a junction is equal.
Parallel circuits have multiple
paths for the electricity to flow.
Junction
(current splits)
IT
The branches (paths)
of a parallel circuit are
independent: if one
light is unscrewed, the
other will stay on.
The total current equals
the sum of the two
branch currents.
When adding together batteries or resistors, it depends whether they are in series or in parallel.
8V
Objects in parallel have the same voltage
because they share wires (same wire: same voltage).
3V
3V
2A
1.5 V
6V
1.5 V
2A
4
6V
6V
2Ω
2A
0V
9V
Vtotal = 6 V
Vtotal = 3 V
Rtotal = 8
Example 1: Find the total current in this series circuit.
R2 = 2 Ω
Step 3: V = IR
V
Itotal = total
Rtotal
R3 = 3 Ω
Itotal =
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Resistors in parallel reduce total
resistance because there are more
paths for the current to flow.
Example 2: Find the total current in this circuit.
12 volts
Step 2. Rtotal = 1 + 2 + 3
= 6 (in series)
R1 = 1 Ω
Rtotal = 1
Batteries in parallel
share the same voltage
(they just last longer).
Resistors and batteries
in series add together.
Step 1: 12 V
Vtotal =
24 volts 12 V
3Ω
0V
1.5 V
0V
6V
4V
6V
2A
Junction
(current joins)
IT = I1 + I2
Objects in series have the same current
because there is only one path.
4
I2
I1
Your house is wired in parallel, so that each light and
appliance can be turned on and off independently.
The current is the
same everywhere in
a series circuit.
4A
2A
Series versus Parallel
If any part of a series circuit
is broken, the circuit fails.
The lights are dependent on
one another: if either light
is unscrewed both lights
will turn off.
IT
4A
2A
The voltage change 12V
over any wire is zero.
0V 0V
0V
OR
The voltage is the
Batteries add voltage,
same everywhere
resistors
subtract voltage, and
in the same wire.
Multiple Devices
Just like in a river, current can only change
if there is a junction: a split or a join.
Junctions
0V
24
= 4 amps
6
Step 1:
Vtotal =
12 volts
Step 2 :
I branch 2 =
6V
6Ω
3Ω
12v
= 4a
3Ω
6V
0 volts
0 volts
Step 2 : I branch1 =
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12v
= 2a
6Ω
Step 3 :
I total = I 1 + I 2
= 2 + 4 = 6a
Copyright © 2007, C. Stephen Murray
Name: _____________________
Unit 9:4
Period: _____________________
1. Series
A. The voltage across any wire.
1. R1
A. Voltage between A and B.
2. Short Circuit
B. A circuit with multiple paths for current
to flow.
2. VT
B. The total voltage in the circuit.
3. Parallel
C. Where current splits or joins.
3. IT
C. The resistance of resistor 1.
D. An independent path for electricity in a
parallel circuit.
4. V2
D. The current in branch 2 of the circuit.
4. Branch
5. I2
E. Total current in the circuit.
E. When a wire by-passes a part of a circuit. 6. RT
F. A circuit with only one path for the
7. VAB
electricity.
5. Junction
6. Zero
F.
The voltage of battery 2.
G. The total resistance of the circuit.
Are these devices in Series or Parallel?
Series or Parallel Circuit?
A. ______
___ Only one path for the electricity to flow.
B. ______
C. ______
D. ______
___ Paths are dependent on each other (one affects the other).
2V
___ How your house is wired.
9V
2V
6
___ Paths are independent of each other.
5
4
6
9V
___ If one light turns off, the others stay on.
VT = _____
___ If you turn off one light, all the lights turn off.
RT = _____
VT = _____
RT = _____
___ Has more than one path for the electricity to flow.
B
A
___ Two devices have the same current.
C
___ Two devices have the same voltage.
Understanding current.
Fill in the missing information on the following graphics.
6V
4Ω
D
4Ω
6V
4A
3A
IT = 18 A
6A
ITotal = _____
I2 = _____
I = _____
1A
F
G
VT = ______
VFG = ______
VED = ______
VAB = ______
VFB = _______
VAC = _______
VEA = ______
VCE = ______
VDC = _______
A) What is the total voltage above?
B) What is the voltage from B to F?
C) What is the resistance from B to F?
D) Find the current flowing from B to F
(label it on the diagram).
I = _____
1A
E
3A
E) How much current flows from C to G (label it)?
ITotal = _____
Which resistor will have
more current running thru
it?
F) So, using D and E above, what is the total current
going thru point E (this is the total current [IT])?
3V
20 Ω
5Ω
G) Using VT and IT, find the total resistance of the circuit [RT].
3V
Why?
Which light bulb will be brighter?
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Legal copying of this worksheet requires written permission.
Copyright © 2007, C. Stephen Murray