Energy and our Universe - Pearson Schools

54
Series circuit.
BTEC’s own resources
2.9 Understanding electricity
In this section:
Key terms
Series – in a series circuit the
components are connected in a line,
end to end, so that current flows
through all of them one after the other.
Parallel – in a parallel circuit the
components are in separate paths and
the current is split between the paths.
Parallel circuit.
P6
P8
What is electricity?
Electricity is the flow of electrical charge. The charge could be positive
and negative ions, as inside the battery of your mobile phone, or
negatively charged electrons, as in the wire of your DVD player. When
charge flows we say there is a current. Electrical energy allows a current
to flow in a circuit. For example, when your DVD player is connected to
the mains, it forms a circuit. A measure of the energy carried between
two points in a circuit is called voltage or potential difference (pd).
The two points could be each end of the bulb in the circuit shown.
switch
resistor
bulb
V
battery
ammeter
voltmeter
An electric circuit diagram of a bulb, switch, fixed resistor, voltmeter and ammeter.
We use a voltmeter to measure voltage and an ammeter to measure
current. The way we connect the meters is important. A voltmeter is
always connected in parallel. An ammeter is connected in series. The
picture above shows a typical circuit diagram of a light bulb with the
symbols of the different components.
Case study: Fault finder
Imagine your world without electricity: no
lights, no television, no central heating, no
shower. It would be a strange place.
Sophia is a technician at an electronics company. Today she is
repairing a DVD player that seems to have no power. She wants to
measure the voltage and find out if there is a break in the circuit.
How could she do this?
A