Question

derive principle of wheat stone bride using kirchoff law​

Answer 1

Answer:

Kirchoff's Law states that the algebraic sum of currents at a junction of an electric circuit is zero. ... Wheatstone bridge is formed by connecting a battery B or an electric source, a plug key K and a variable resistor X between the junctions A and D and a galvanometer G between the junctions C and D [Figure]

Answer 2

Explanation:

Kirchhoff's law: To study complex circuits, kirchhoff's gave following too laws:

(i) If a network of conductors the algebraic sum of all currents meeting at any junction of my circuit is always zero.

i.e. ∑I=0

(ii) In any closed mesh (or loop) of an electrical circuit the algebraic sum of the product of the currents and resistance is equal to the total e.m.f. of the mesh.

i.e. ∑IR=∑E

Formula Derivation: Referring fig.

Four resistances P, Q, R and S are connected to form a quadrilateral ABCD. A cell E is connected across the diagonal AC and a galvanometer across BD. When the current is flown through the circuit and galvanometer does not give any deflection, then the bridge is balanced and when the bridge is balanced, then

Q

P

=

S

R

This is the principle of Wheatstone bridge.

Let the current i is divided into two parts i

1

and i

2

flowing through P, Q and R, S respectively. In the position of equilibrium, the galvanometer shows zero deflection, i.e. the potential of B and D will be equal.

In the closed mesh ABDA, by Kirchhoff's second law, we get

i

1

P−i

2

R=0

or i

1

p=i

2

R ........(i)

Similarly, in the closed mesh BCDB, we have

i

1

Q−i

2

S=0

or i

1

θ=i

2

S .......(ii)

Dividing equation (i) by equation (ii) we get

i

1

Q

i

1

P

=

i

2

S

i

2

R

Q

P

=

S

R

This is the condition for balance of wheatstone bridge.

hope it helps you buddy