Series and
Parallel Circuits
In
this section we will look at how batteries, switches and
lamps can be connected in either series or parallel. To help
us do this we will use a "multimeter" to see what is happening
to the voltages inside the circuits.
To
begin, you will need to find out how to measure
voltage with a multimeter:-
Open the "using a multimeter" link at the top of this screen
and carefully read sections 1 and 2. Then read the part
headed "Measuring Voltage" before continuing.
The
multimeter below has had its centre dial turned round to
read up to 20 Volts. We can now use it to check the voltage
(potential difference) across the two terminals of our single
battery.
Move
the battery
between the
meter's red (+) and
black (-) probes.
The meter will
then display the
voltage of the
battery.
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Q17,
The voltage on the + side of the battery is
measured on the red probe at 1.5volts. Is this higher
(more positive) or lower (more negative) than the zero
voltage on the - side of the battery?
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If the batteries are
connected as shown so that
the + side of one connects
to the - side of the other
then the total voltage is :-
1.5
volts + 1.5 volts
= 3
volts.
Torches
often have two or
more batteries in series to
increase their power.
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In this arrangement
the +
side and - side of each
battery is connected
together so that the
combined voltage remains
at 1.5 volts.
Batteries connected
in
parallel, like
this, can
provide more power than
a single battery. This is
because they are able to
provide twice the current.
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The slider
switches in this
circuit are "on",
when they are
put to the "1"
position.
Click
the
switches to
make the light
work.
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Try
clicking the
switches again
to see if both
have to be on
for the light to
work.
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