What is Meter bridge?
Meter bridge is also called as slide wire bridge and is an instrument that works on the principle of Wheatstone bridge.A meter bridge is used to find the unknown resistance of a wire as that of in a Wheatstone bridge.It can also used to find the resistivity of the material of a wire and the effective series and parallel equivalent combination of resistors.Meter bridge:Circuit diagram and construction
Meter bridge :Circuit Diagram
Meter bridge:Construction
The meter bridge consists of a one meter long wire of uniform cross sectional area and it has two different sections,which is left and right sections, fixed on a wooden block.One meter long scale is attached to the wooden block. Two L shaped copper strips and an another copper strip are also fixed on that wooden block.
The copper strips are fixed in such a way that they form two gaps in order to make the Wheatstone bridge.The terminal B between the gaps is used to connect a galvanometer and a pencil jockey.The jockey which detects the balancing point
Meter bridge:Experimental setup
Procedure for finding the unknown resistance using meter bridge
Meter bridge works on the principle of Wheatstone bridge balance conditions. The circuit connections/experimental set up is shown here.
Once the circuit connections are completed, the jockey is pressed near the end A and then near end B of the meter bridge wire.
A suitable value of known resistance is introduced in the dial/plug type resistance box. Select the values of known resistance R for which the balancing length is close to the middle point of the meter bridge wire. The pencil jockey is moved gently over the meter bridge wire to find the null deflection in the galvanometer.
If the deflections in the galvanometer are on one side, then there is some fault in the circuit connections. Check for double side deflections in the galvanometer.
Interchange the positions of X and R and repeat the experiment. The observed values are tabulated and the mean value of the unknown resistance can be calculated.
Balanced condition of Wheatstone bridge
Meter Bridge Numericals
NUMERICAL -1
NUMERICAL-2
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