Page 32 - CITS - Electrician - Trade Practical

ELECTRICIAN - CITS

EXERCISE 8 : Measure the current and voltage in

electrical circuits to verify Kirchhoff’s Law

Objectives

At the end of this exercise you shall be able to:
• verify the Kirchhoff’s Voltage Law - KVL
• verify the Kirchhoff’s Current Law – KCL
• measure the voltage, current & resistance in complex circuit networks.

Requirements

Tools/Equipments/Instruments
• Combination plier 150mm -1 No. • Rheostat 0-300 Ω, 3A - 1 No.
• Side cutter 150mm -1 No. • Rheostat 0-700 Ω, 1A - 1 No.
• Screw driver set 150mm -1No. • Rheostat 0-400 Ω - 1 No.
• Variable DC power supply Materials/Components
0-200 v DC -1 No.
• Ammeter 0-1 A, MC -3 No’s. • PVC copper wire 1.0 sq mm - as reqd.
• Volt meter 0-250 V, MC -4 No’s.

Procedure

TASK 1: Verify Kirchhoff’s Voltage Law - KVL
1 Draw the circuit diagram.
2 Mark the polarity of the voltage drops across the resistors.
3 Make the connections as per circuit diagram.

4 Switch ON the power supply and set to 50 V.
5 Measure and record the voltage drops across the resistors.
6 Repeat these steps by setting the voltages to 100 V, 150 V and 200 V
7 Write the Kirchhoff’s voltage equations for the closed paths. In any closed path he algebraic sum of all the
voltages is zero.ie, V= V +V
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TASK 2: Verify Kirchhoff’s Current Law - KCL
1 Draw the circuit diagram for KCL.
2 Make the connections as per circuit diagram.

3 Keep the regulated power supply OFF while making connections.
4 Keep the voltage control knob at minimum.
5 Switch ON the Power supply. Set the supply voltage to 50 V.
6 Measure and record total circuit current I and branch currents I and I .
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7 Repeat these steps by setting the PS voltages to 100 V and 150 V.
8 Write the Kirchhoff’s current equation. The algebraic sum of currents meeting at a node equal to zero. Σ I=0
ie, I = I + I
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9 Verify the equation by substituting the measured values.

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