Page 26 - CITS - Electrician - Trade Practical

ELECTRICIAN - CITS

MODULE 2: Basic Electrical Circuits

EXERCISE 5: Verification of Ohms law

Objectives

At the end of this exercise you shall be able to
• make the circuit connections of ohms law
• measure the voltage, current & resistance in electrical circuit
• verify the ohms law by keeping circuit resistance constant
• verify the ohms law by keeping supply voltage constant.

Requirements
Tools/Equipments/Instruments

• Combination Plier 165mm, • Voltmeter MI, 250 V -1 No.
insulated -1 No. • Ammeter MI, 10 Amp -1 No.
• Screw driver 150 mm, • Digital Multi meter 3 ½ Digit -1 No.
insulated stem -1 No. Materials/Components
• Neon Tester 75mm, 500 V -1 No.
• Electrician Knife Insulated -1 No. • PVC copper wire 1.5 sq.mm - as reqd.
• Rheostat 300 Ω, 5 Amp -1 No. • DP switch 250 V, 16 A - 1 No.
• 1 Ph. Auto Transformer
0 - 270 V, 5 A -1 No.

Procedure

TASK 1: Verify the ohms law with variable resistance & constant voltage method.
1 Draw the circuit diagram of ohms law verification.
2 Make the connections of ohms law method-1 as per the circuit diagram.
3 Check the connections and switch ON the supply.
4 Note down voltmeter & Ammeter readings.

5 Keep the supply voltage constant and vary the resistance step by step in Rheostat.
6 Note down the voltmeter & Ammeter readings in each steps.
7 Verify the ohms law I = V/ R with measured values and plot the graph.

TASK 2: Verify the ohms law with variable voltage & constant resistance method.

1 Make the connections of method-2 as per the circuit diagram.
2 Check the connections and switch ON the supply.
3 Keep the circuit resistance constant and vary the input voltage step by step with Auto Transformer.
4 Note down the voltmeter & Ammeter readings in each steps.
5 Verify the ohms law I = V/ R with measured values and plot the graph.

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