## EE6511 CI LAB Manual

Anna University Regulation 2013 EEE EE6511 CI Lab Manual viva voce question for all experiments is provided below. Download link for EEE 5th SEM EE6511 Control Instrumentation Laboratory Manual is listed down for students to make perfect utilization and score maximum marks with our study materials.

Anna University Regulation 2013 EEE 5th SEM EE6511 CI LAB-Control Instrumentation Laboratory Manual

### 1(b). KELVIN’S DOUBLE BRIDGE

AIM:

To measure the given low resistance using Kelvin’s Double bridge.

THEORY:

Kelvin’s double bridge is a modification of Wheatstone’s bridge and provides more accuracy in measurement of low resistances It incorporates two sets of ratio arms and the use of four terminal resistors for the low resistance arms, as shown in figure. Rx is the resistance under test and S is the resistor of the same higher current rating than one under test. Two resistances Rx and S are connected in series with a short link of as low value of resistance r as possible. P, Q, p, q are four known non inductive resistances, one pair of each (P and p, Q and q) are variable. A sensitive galvanometer G is connected across dividing points PQ and pq. . The ratio P Q is kept the same as p q , these ratios have been varied until the galvanometer reads zero.

PROCEDURE:

1. Connect the unknown resistance Rx as marked on the trainer

2. Connect a galvanometer G externally as indicated on the trainer

3. Energize the trainer and check the power to be +5 V.

4. Select the values of P and Q such that P/Q = p/q = 500/50000 = 0.01

5. Adjust P1 for proper balance and then at balance, measure the value of P1.

REVIEW QUESTIONS

1. Name the bridge used for measuring very low resistance.

2. Classify the resistances according to the values.

3. Write the methods of measurements of low resistance

4. What is the use of lead resistor in kelvin’s Double bridge?

5. Why Kelvin’s double bridge is having two sets of ratio arms?

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