Meter Bridge or Slide Wire Bridge—

it is an arrangement based on the principle of Wheatstone Bridge used to measure an unknown resistance.

Construction—

It consists of a one meter long uniform wire connected with two cupper strips fixed on a wooden board. Between these two strips, another strip is also fixed and all three provide two gaps. A Resistance Box and Unknown Resistance are connected in these two groups. Now we connect one terminal of galvanometer to the middle strip and a jockey is connected to the second terminal of the galvanometer.

Now, we slide jockey on the meter wire and we get a length (say l) at which we get balanced condition means zero current in galvanometer arm. So we have four resistances

P as a lσ, Q as a (100-l)σ, R as a Resistance Box and S as an Unknown Resistance, so as per Wheatstone Bridge