Wheatstone Bridge Experiment Sheet
Schematic of the Wheatstone Bridge
$R_1$ - Resistance of left side of the string.
$R_2$ - Resistance of right side of the string.
$R_3$ - Resistance of the resistor box.
$R_x$ - Unknown resitor.
The implementation of the above schematic is shown here:
Resistance of the wire is directly proporional to it's length,
$$
R_1 = \rho \frac{l_1}{S}, \qquad R_2 = \rho \frac{l_2}{S}
$$
Here $S$ is cross sectional area of the string, $\rho$ is resistivity of the string material, $l_1$ and $l_2$ are
lengths of right and left side of the strings respectively.
Resistance of unknown resistor could be obtained by following formula when bridge is balanced:
$$
R_x = \frac{R_2}{R_1} R_3 = \frac{l_2}{l_1} R_3
$$
Length of the ruler is $l = 35$cm.
Experiment sheet:
|
#
|
$R_3$ [$\Omega $]
|
$l_1$ [cm]
|
$l_2 = l - l_1$ [cm]
|
$R_{x}$ [$\Omega $]
|
| 1 |
|
|
|
|
| 2 |
|
|
|
|
| 3 |
|
|
|
|
| 4 |
|
|
|
|
| 5 |
|
|
|
|
| 6 |
|
|
|
|