# Why Are Some Resistors in Parallel While Others Are Not?

• User1265
In summary, the conversation discusses the difficulty in determining which resistors are in parallel in a circuit. The speaker attempts to solve the problem by considering the resistors in parallel and using the concept of short circuiting. However, they encounter a roadblock and express confusion on how to identify parallel resistors. The conversation ends with a suggestion to find a path from one side of one resistor to the other side of another resistor to determine if they have the same potential difference.
User1265
Homework Statement
Find the current of i1 and i2
Relevant Equations
V/R = i

E=V+IR
My attempt at a solution:
I can see the two resistors at the bottom are in parallel as shown on the circuit diagram attached, but I'm failing to understand why there's a third resistor in parallel.
So I made it one effective resistance as R/2.
Then I proceded to think the circuit short circuits, as Resitor in the middle + R/2 at the bottom has a lower resistance than resistor at the top + middle resistance. So I though i1 = 0 ... I felt like this was wrong and stopped my solution here.

I have been told in order to determine if resistors are in parallel, you must see if the same pd is applied across them, but struggling to see how I can do this here. How do I indentify which are in parallel in this case?

#### Attachments

• 2019-10-19 (1).png
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User1265 said:
How do I indentify which are in parallel in this case?
If you can find a path from one side of resistor A to one side of resistor B that does not encounter any components, and similarly for the other sides of the two resistors, then the same PD applies across both.

## What is the purpose of resistors in parallel?

Resistors in parallel are used to divide the current in a circuit, allowing for more control over the flow of electricity. They also help to reduce the overall resistance of the circuit.

## How are resistors in parallel connected?

Resistors in parallel are connected side by side with each other, rather than in a series. This means that the positive ends of all the resistors are connected together, as are the negative ends.

## What is the formula for calculating the total resistance of resistors in parallel?

The formula for calculating the total resistance of resistors in parallel is 1/Rt = 1/R1 + 1/R2 + 1/R3 + ..., where Rt is the total resistance and R1, R2, R3, etc. are the individual resistances.

## How does the total resistance of resistors in parallel compare to the smallest individual resistance?

The total resistance of resistors in parallel will always be less than the smallest individual resistance. This is due to the fact that the current has multiple paths to flow through, reducing the overall resistance.

## What happens to the overall current when resistors are added in parallel?

Adding resistors in parallel will increase the overall current in the circuit. This is because the total resistance is decreased, allowing for more current to flow through the circuit.

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