DC Circuits
RESISTORS
IN PARALLEL
Question
In the following schematic diagram, find the total current, I.
Figure 1 Example Problem: Resistors in Parallel
Hints
-
You will need Ohm's Law.
-
How are resistors related when connected in parallel?
-
What is the potential drop across each resistor?
-
How does current behave in parallel branches?
Solution
We know the total potential of this circuit,
= 12.0 V
So, between points A and B, the potential must drop 12.0V. Also, the potential
drop across branches of a circuit are equal. That is,
We can use Ohm's Law
or
to find the current across each resistor.
Recall that the currents through branches of a parallel circuit add to
give the total current. That is, the total current 'splits up' so that
part of the total current travels down each branch. Because of conservation
of charge, the sum of the currents in each branch must equal the amount
going into the branch. (This is Kirchhoff's Current
Law.)
So, adding up the three currents, we get:
So, the total current is I = 12.0A.
Explanation
of Resistors in Parallel
Continue
to:Resistors in Combination
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