Resistance in a Parallel Circuit.
The total resistance of a parallel circuit is calculated using the formula
1/R = 1/R1 + 1/R2 + 1/R3 ·····
In the above circuit,
1/R = 1/2 + 1/3 + 1/4
= 6/12 + 4/12 + 3/12
= 13/12
R = 12/13
= 0·92 Ohms.
Notice that this is a much smaller resistance
than you get in the series circuit
using the same
resistors.
It is even
smaller than the smallest
resistor in the parallel circuit,
which is 2 Ohms.
Putting more resistors in the
parallel circuit decreases the
total
resistance
because the electricity has
additional branches to flow
along
and so the total
current flowing increases.
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