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Simple circuits worksheet Simple circuits worksheet
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This worksheet covers the following concepts:
How to build simple battery-powered circuits.
Relating illustrations to schematic diagrams, and visa-versa.
Basic meter usage (measuring voltage, current, and resistance).
Using meters to measure electrical quantities on a printed circuit board.
Dierent types of electrical switches.
Simple series and simple parallel light bulb circuits.
Resistors and their function.
Troubleshooting a simple light bulb circuit.
Resources and methods for learning about these subjects (list a few here, in preparation for your
research):
1 Questions
Question 1
In the simplest terms you can think of, dene what an electrical circuit is.
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Question 2
Given a battery and a light bulb, show how you would connect these two devices together with wire so
as to energize the light bulb:
+
-
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2 Question 3
Build a simple electric circuit using a battery as the electrical energy source, and a small light bulb as
the electrical load (I suggest using a 6-volt lantern battery and a miniature incandescent light bulb rated
for either 6 or 12 volts). Use jumper wires with metal clips at the ends to join these two electrical devices
together:
+
-
Battery
Light bulb
"Jumper" wire
"Jumper" wire
After connecting the components together properly so the light bulb lights up, answer the following
questions:
What conditions must be met for the light bulb to light up?
What happens if the circuit is broken?
Does it matter where the circuit is broken?
Then, add a third jumper wire to the circuit so you have a ready break to experiment with:
+
-
Break in circuit
Try bridging this break with various materials, and note whether or not the light bulb lights up:
Paper
Steel paper clip
Gold ring
Rubber eraser
Pencil lead (graphite)
Also, try touching the jumper wire ends together along their plastic exteriors, rather than at the metal
clip ends. Does the light bulb light up when you do this?
3 Explain what this experiment demonstrates about the electrical conductivity of the various substances
listed as well as the plastic coating of the jumper wires. Also explain why electrical wires are provided with
that plastic coating, instead of being bare metal. Finally, explain what this experiment has taught you about
electric circuits in general.
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Question 4
What dierence will it make if the switch is located in either of these two alternate locations in the
circuit?
Switch on negative side of circuit
Switch on positive side of circuit
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Question 5
What dierence will it make if the battery in this circuit is reversed in direction?
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4 Question 6
Examine this schematic diagram:
Light bulb
Switch
Battery
Now, without moving the following components, show how they may be connected together with wires
to form the same circuit depicted in the schematic diagram above:
+
-
Battery
Light bulb
Switch
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Question 7
What will this voltmeter register when connected to a battery as shown (assume a battery voltage of 6
volts)? Explain your answer.
COM
A
V
V
A
A
OFF
+
-
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5 Question 8
What will this voltmeter register when connected to a battery as shown (assume a battery voltage of 6
volts)? Explain your answer.
COM
A
V
V
A
A
OFF
+
-
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Question 9
Determine what these four voltmeters (A, B, C, D) will register when connected to this circuit in the
following positions (assume a battery voltage of 6 volts):
switch open
V COM
A
V
V COM
A
V
V COM
A
V
V COM
A
V
A
B
C
D
Voltmeter A =
Voltmeter B =
Voltmeter C =
Voltmeter D =
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6 Question 10
Determine what these four voltmeters (A, B, C, D) will register when connected to this circuit in the
following positions (assume a battery voltage of 6 volts):
V COM
A
V
V COM
A
V
V COM
A
V
V COM
A
V
A
B
C
D
switch closed
Voltmeter A =
Voltmeter B =
Voltmeter C =
Voltmeter D =
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7 Question 11
Why is it a very bad idea to connect an ammeter directly across a voltage source, like this?
COM
A
V
V
A
A
OFF
+
-
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8 Question 12
In this circuit, is the light bulb lit? Why or why not?
Also, compare the relative indications of the two ammeters (which ammeter registers the greatest amount
of current, and which ammeter registers the least amount of current, or do they both register the same amount
of current?).
switch open
V COM
A
V COM
A
B
A
A
A
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9 Question 13
In this circuit, is the light bulb lit? Why or why not?
Also, compare the relative indications of the two ammeters (which ammeter registers the greatest amount
of current, and which ammeter registers the least amount of current, or do they both register the same amount
of current?).
V COM
A
V COM
A
B
A
A
A
switch open
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10 Question 14
In this circuit, is the light bulb lit? Why or why not?
Also, compare the relative indications of the two ammeters (which ammeter registers the greatest amount
of current, and which ammeter registers the least amount of current, or do they both register the same amount
of current?).
V COM
A
V COM
A
B
A
A
A
switch closed
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Question 15
Explain how an ohmmeter is able to measure the resistance of a component (in this case, a light bulb)
when there is no battery or other source of power connected to it:
COM
A
V
V
A
A
OFF
Also, identify the reading you would expect the ohmmeter to indicate if the light bulb were burnt out
(failed open).
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11 Question 16
Shown here is a circuit constructed on a PCB (a Printed Circuit Board), with copper traces serving
as wires to connect the components together:
-
-
+
-
R1
C1
Printed circuit board
Battery
SW1
COM
A
V
V
A
A
OFF
How would the multimeter be used to measure the voltage across the component labeled R1 when
energized? Include these important points in your answer:
The conguration of the multimeter (selector switch position, test lead jacks)
The connections of the meter test leads to the circuit
The state of the switch on the PCB (open or closed)
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12 Question 17
Shown here is a circuit constructed on a PCB (a Printed Circuit Board), with copper traces serving
as wires to connect the components together:
-
-
+
-
R1
C1
Printed circuit board
Battery
SW1
COM
A
V
V
A
A
OFF
How would the multimeter be used to measure the current through the component labeled R1 when
energized? Include these important points in your answer:
The conguration of the multimeter (selector switch position, test lead jacks)
The connections of the meter test leads to the circuit
The state of the switch on the PCB (open or closed)
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13 Question 18
What would happen if a multimeter were connected across the component labeled C1 on this printed
circuit board, as shown?
-
-
+
-
R1
C1
Battery
SW1
COM
A
V
V
A
A
OFF
Switch ON
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14 Question 19
Shown here is a circuit constructed on a PCB (a Printed Circuit Board), with copper traces serving
as wires to connect the components together:
-
-
+
-
R1
C1
Battery
SW1
COM
A
V
V
A
A
OFF
How would the multimeter be used to measure the resistance of the component labeled R1? Include
these important points in your answer:
The conguration of the multimeter (selector switch position, test lead jacks)
The connections of the meter test leads to the circuit
The state of the switch on the PCB (open or closed)
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15 Question 20
The circuit shown here is called a bridge rectier, and its purpose is to convert alternating current
(from the power-supply unit) into direct current. Suppose you were instructed to check the continuity of
the switch (SW1) mounted on the printed circuit board. What would be a fast and eective way of testing
this switchs continuity (ideally, without removing the switch from the circuit board)?
SW1
D1
D2
D3
D4
Low-voltage
AC power supply
6
6
12
R1
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Question 21
Identify the