# Verify KCL and KVL

Aim:- To study and verify Kirchhoff's Current Law (KCL) and Kirchhoff's Voltage Law (KVL).

Apparatus Required:-

 S. No. Name of Equipment Type Range Quantity 1. Ammeter PMMI 0-10A. 0-15A 2, 1 2. Voltmeter PMMI 0– 300V 3 3. Inductive Load - - 1 4. Connecting Wire Copper 0-10 A (2mm) -

Theory:- Kirchhoff's had discovered two basic laws dealing with electrical circuit, namely current law and voltage law. These two laws are extremely useful in solving complex electrical circuit. Kirchhoff's current law is applicable at a node of the network where two or more than two branches are connecting together This law state that in any electrical network, the algebraic sum of the current in all branches meeting at a node is zero i.ee/= 0.

Kirchhoff's voltage law is applicable to a closed mesh of the network. A closed mesh may consist of number of resistance branches only or a branch addition with source of EMF. Kirchhoff's voltage law states that the algebraic sum of the product of current and resistance of various branches of a closed mesh plus the algebraic sum of the EMF in that closed mesh is equal to zero i.e. V +SIR = 0.

Circuit Diagram:-

Observation Table:

Kirchhof’s Current law

 S. No. A1­ (Amps) A2 (Amps) A3 (Amps) A= % Error 1. 3.2 2.3 2.3 3.25 1.56 2. 5.0 3.9 3.2 5.04 0.8 3. 6.6 5.2 3.9 6.50 0.15 4. 8.4 6.8 4.6 8.20 2.9 5. 10.0 8.1 5.3 9.67 3.3

Kirchhof’s Voltage law

 S. No. V1­ (Volts) V2 (Volts) V3 (Volts) V= % Error 1. 236 52 220 226.06 4.23 2. 236 92 208 227.43 3.6 3. 236 120 192 226.41 4.08 4. 236 144 172 224.32 4.95 5. 236 152 152 214.96 8.49

Procedure:-

KCL

1.     First measure the least count of all ammeters A1, A2 and A3 and all voltmeters V1, V2 and V3.

2.     Connect the circuit as shown in the diagram.

3.     Now, vary both the resistive and inductive load to obtain different readings of ammeters A1, A2 and A3. Repeat the procedure for different observations.

4.     Calculate percentage error

KVL

1.     Connect the circuit as shown in the diagram.

2.     Now, adjust both the rheostat and inductive load to obtain different values of then take V1, V2 and V3.

3.     Repeat the same procedure for different observations.

4.     Calculate percentage error.

Calculation:-

KCL                                                                      KVL

% Error =  (A2-A3)/A1 x100                                       % Error = (V2-V3)/V1 x100

% Error = 1.56 %                                                     % Error = 4.23 %

Precaution:-

1.     Make the connections properly.

2.      Note the readings of voltmeters and ammeters properly.

3.     Remove insulations from the connecting wire so as the current will flow properly.

4.     Avoid loose connections and don't touch wire with wet hand.