Transcript Parallel / series resistor & capacitors

When two or more
components are connected in
a line, this is called a series
connection (left of picture).
 When they are connected
across each other it is called a
parallel connection (right of
picture).
 This module looks at how to
calculate the combined
resistance or capacitance of
both of these connections.
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Let's start with resistors connected
in series. The function of a resistor
is to limit the flow of current. The
bigger the resistance the more
the current is limited.
When we connect two resistors
together, each resistor limits the
current in turn so the total
resistance is more than either
individual resistor.
The total resistance (Rt) is the sum
of all the resistors:
Rt = R1 + R2 + R3 + .... + Rn
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When resistors are connected in
parallel, the current can flow
down any of the resistors. This
makes it easier for the current to
flow and the overall resistance is
decreased. If two equal value
resistors are connected in parallel
then the current splits evenly
through them and the total
resistance is half the individual
value. As the values are normally
different, we can use the
following equation:
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Although this equation looks
complicated, most calculators
have a 1/x key or a reciprocal
key.
Suppose R1 = 100 and R2 = 50,
then on a calculator you would
enter:
100 followed by 1/x (= 0.01)
50 followed by 1/x (=0.02)
Add the terms together 0.01 +
0.02 = 0.03
Finally press 1/x to give 33.3
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Capacitors are made of a pair
of metal plates that hold charge,
the bigger the plates the more
charge they can hold.
Effectively by connecting two
capacitors in parallel we make
one capacitor with bigger
plates, which has a bigger
capacitance. The total
capacitance (Ct) is calculated
by adding each of the
capacitance's together:
Ct = C1 + C2 + C3 + ... + Cn
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When capacitors are
connected in series the
overall capacitance is
lower than the individual
values. It is calculated in
the same way as parallel
resistors. The total
capacitance (Ct) is: