Parallel Circuit Analysis

Another basic circuit type is the parallel circuit, in which there is more than one current path. To analyze resistors in a series circuit, we found an equivalent resistance. We’ll follow the same strategy in analyzing resistors in parallel.

Resistors in Parallel

Let’s look at a circuit made of the same components we used in our exploration of series circuits, but now we’ll connect our components so as to provide multiple current paths, creating a parallel circuit.

Regents Physics Parallel Circuit

Notice that in this circuit, electricity can follow one of three different paths through each of the resistors. In many ways, this is similar to a river branching into three different smaller rivers. Each resistor, then, causes a potential drop (analogous to a waterfall), then the three rivers recombine before heading back to the battery, which we can think of like a pump, raising the river to a higher potential before sending it back on its looping path.

We can find the equivalent resistance of resistors in parallel using the formula:

Regents Physics Parallel Resistors

Take care in using this equation, as it’s easy to make errors in performing your calculations. Let’s see if we can find the equivalent resistance for our sample circuit.

Regents Physics Parallel Resistor Calculation

 

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