- #1

Safder Aree

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## Homework Statement

Given this following circuit:

What is the internal resistance of the meter movement ( R_I).

This is part of a project I'm doing and I know the equation that gives you the internal resistance in this circuit.

$$R_I = \frac{R_sR_p}{R_s - R_p}$$.

However, I have no idea how this is derived. I know the values for V, R_s and R_p as it was done experimentally.

## Homework Equations

$$R_I = \frac{R_sR_p}{R_s - R_p}$$.

$$ V = IR $$

## The Attempt at a Solution

Using circuit analysis I can simplify the parallel portion as:

$$ R_{parallel} = \frac{1}{R_p} + \frac{1}{R_I}$$

Thus:

$$R_{total} = R_s + \frac{1}{R_p} + \frac{1}{R_I} $$

But what is R_total, how do I get rid of it?

Thank you for any guidance.

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