Part 1 - Series and Parallel circuits
1. Draw an example of a series circuit in the space below; include a battery, two lamps
and an ammeter:
2. Draw an example of a parallel circuit below, using the same components as the one
above:
3. What is the key difference between the two types of circuit? Use the word current in
your answer.
Part 2 - Current in series circuits
1. Consider the following circuit. If we took away one of the cells, what would happen
to the brightness of the lamps?
2. If lamp number 3 were to burn out, what would
happen to the other lamps?
3. If this were to happen, current would still be
flowing. (Circle the correct answer)
True
False
4. Use this to write out a rule about components and current in a series circuit below:
You need to be aware of the following rules to work through the next questions.
-
Current in a series circuit is the same at all parts in a circuit.
-
An ammeter measures the amount of current flowing past a certain point
-
Ammeters are always connected in series, not parallel
1. A student sets up the following circuit. What has she done incorrectly?
2. Draw the correct setup using the same components below:
3. Ammeter 1 shows a reading of 0.3A. What are the readings of the other
ammeters?
A2 = ________ Amps
A3 = ________ Amps
Part 3- Current in parallel circuits
You need to be aware of the following rules to work through the next questions.
- In a parallel circuit, the total
current entering a junction must
equal the total current leaving
that junction (see the diagram on
the right).
-
The parallel circuit splits into 3
routes; this means the current
also splits into 3 equal amounts.
Therefore, 9/3 = 3Amps
-
Parallel circuits can be thought of as many little circuits in one; if one of these circuits
had a gap, there may still be another route for current to flow. Keep this in mind
when considering components, such as lamps.
1. In the circuit diagram above, what would the current at the star (
) read?
_________A
2. What are the readings on the ammeters n this circuit?
A1 = _________A
A2= _____________A
3. Consider the circuit below. If A1 shows a reading of 6A, what are the values of
the other ammeters? Show your working!
Working out
A2 = __________
A3 = __________
A4= ___________
4. Consider the circuit below. If A3 shows a reading of 0.2A, what are the values of
the other ammeters? Show your working!
Working out
5. Consider the following circuits. If
the star represents a gap, which
lamps would be affected? Put a tick
A2 = __________
next to the bulbs that are still lit!
A4 = __________
A1= ___________
-
If you haven’t already, get your answers checked at this point! Well done so far! 
Voltage and Voltmeters in circuits
You need to be aware of the following rules to work through the next questions.
- Always connect voltmeters in parallel, across an electrical component (across, not in
line with it! This is different to how ammeters are connected!) as shown by the
diagrams below.
- In a series circuit, the total, or sum of the voltages across all the components will
equal the voltage across the cell/battery
The total voltage supplied by the
cell is 12V. There are three lamps
connected in series, so 12/3 =
4V.
If there were four lamps, and the
same cell, each voltmeter would
read 3V (12/4)
What would each voltmeter read
if there were two lamps?
________V
-
In a parallel circuit, this is the opposite. The voltage across the different components
is the same as the voltage across the cell/battery. It doesn’t matter how many routes
there are.
-
This circuit, the input voltage supplied by the cell is 3V.
This is what the value will be across the other two lamps
in the circuit. It doesn’t matter how many lamps we add,
it will be the same.
-
The voltage will be the same everywhere (as long as the
resistance of each component is the same, but that’s for
tomorrow’s lesson )
-
KEEP GOING! NEARLY THERE! 
Calculate the missing voltmeter readings for each of the situations below. Show your
working each time!
The label on the battery says 5V. If we connected
a voltmeter across each lamp, what would the
1.
readings be?
At lamp 1 - ________V
L1
L2
L3
At lamp 2- ________V
At lamp 3- ________V
Explain your answer/show your working
2. Calculate all ammeter and voltmeter readings from the diagram below. Remember
to show your working!
V1 = _________
V2 = ______________
A1 = _________
A2 = ______________