Series and Parallel Circuits
Pre-Questions
1. What is an electric circuit?
2. What items are necessary to create an electric circuit?
3. How can you determine if a schematic shows a parallel or series circuit?
Procedure
1. Go to http://phet.colorado.edu/simulations/sims.php?sim=Circuit_Construction_Kit_DC_Only
2. Click “Run now.”
Assignment #1 – One Light Bulb in SERIES CIRCUIT
1. Build this circuit:
What do the blue dots represent?
From which end of the batteries are they flowing?
2. Select the “Voltmeter” tool from the right side and connect
it to your circuit as shown below.
What does the voltmeter read?
(Use proper units)
Take one of the batteries away
happens to the light bulb? What
3. Now, use the “Non-contact
to
points around the circuit. What do you notice?
and connect the circuit. What
happens to the voltmeter reading?
Ammeter”
measure the current at various
Assignment #2 – Testing SERIES CIRCUITS
1. Draw a schematic for a series circuit with three batteries, one switch, and two lights.
2. Build this circuit in the simulator and complete the table
Voltage across the batteries
Voltage across light one
Voltage across light two
Current after batteries
Current after light two
Current after light one
3. Add a resistor after the second light. What happens to the brightness of the light? Complete the
table.
Voltage across the
Voltage across light
Voltage across light
Voltage across
batteries
one
two
resistor
Current after batteries
Current after light one
Current after light two
Current after resistor
4. Remove one battery and connect the circuit. What happens to the brightness of the light?
Complete the table.
Voltage across the
Voltage across light
Voltage across light
Voltage across
batteries
one
two
resistor
Current after batteries
Current after light one
Current after light two
Current after resistor
5. Take out three different wires from the circuit, one at a time and replacing it. What happens to
the lights when wires are removed?
Assignment # 3 – Testing PARALLEL CIRCUITS
1. Draw a schematic for a parallel circuit with one batteries, one switch, and two lights.
2. Build this circuit in the simulator and complete the table
Voltage across the batteries
Voltage across light one
Voltage across light two
Current after batteries
Current after light two
Current after light one
3. Add a resistor in a third parallel circuit. What happens to the brightness of the light? Complete
the table.
Voltage across the
Voltage across light
Voltage across light
Voltage across
batteries
one
two
resistor
Current after batteries
Current after light one
Current after light two
Current after resistor
4. Add one battery and connect the circuit. What happens to the brightness of the light?
Complete the table.
Voltage across the
Voltage across light
Voltage across light
Voltage across
batteries
one
two
resistor
Current after batteries
Current after light one
Current after light two
Current after resistor
5. Take out three different wires from the circuit, one at a time and replacing it. What happens to
the lights when wires are removed?
6. Draw a schematic for a parallel circuit with two batteries and three lights each controlled by its
own switch.
7. Build this circuit in the simulator and complete the table
Voltage across the
Voltage across light
Voltage across light
batteries
one
two
Current after batteries
Current after light one
Current after light two
Voltage across light
three
Current after light
three
Assignment #4 – Reflection Questions:
1. Using the tables from series circuits – how does adding a resistor impact the voltage throughout
the circuit? Why (use Ohm’s Law to explain)?
2. Using the tables from series circuits – how does adding a resistor impact the current
throughout the circuit? Why?
3. Using the tables from parallel circuits – how does adding a resistor impact the voltage
throughout the circuit? Why?
4. Using the tables from series circuits – how does adding a resistor impact the current
throughout the circuit? Why?
5. How does the type of circuit affect the brightness of two light bulbs?
6. When is a series circuit beneficial? Give an example of a series circuit that you are familiar with.
7. When is a parallel circuit beneficial? Give an example of a parallel circuit that you are familiar
with.