1.a. Discuss limitations of Wheatstone bridge and explain how low resistance is measured by KDB.

1.b. For an ac bridge evaluate unknown impedance in the arm DC when bridge is balanced at 2 khz with following components in each arm.

Arm AB : 10 $ k \Omega$
Arm BC : 100 $ \mu f$ series with 100 $k \Omega$
Arm AD : 50 $k \Omega$

Detector is connected between B and D.

2.a. Obtain the dimensional equations in SI units for

1. Absolute permeability
2. Absolute permittivity

2.b. Discuss how capacitance of the capacitor is measured by Schering bridge.

3.a. Reproduce the errors in 1-$\Phi$ kWh meter and explain how energy meter calibrated.

3.b. A 1-$\Phi$ energy mete operating at normal 1-$\Phi$ voltage has a constant load of 4 A passing through it for 6 hrs at 0.8 power factor. If the meter disc makes 2209 revolutions during this period, what is the meter constant in revolutions/kWh? Calculate the power factor of the load if the number of revolutions made by meter 1472 hen operated at normal 1-$\Phi$ AC supply at 5 A for 4 hrs.

4.a. Explain the construction and operating principle of Weston frequency meter and 1-$\Phi$ pf meter.

4.b. Discuss phase sequence indicator.

4.c. A Wattmeter has current coil and pressure resistance of 0.2 $\Omega$ and 5000 $\Omega$ respectively. Evaluate the percentage of error in the Wattmeter reading when load takes 20 A, at 250 V with 0.8 pf tag for two methods of connection of Wattmeter.

5.a. Discuss Silsbee's method of testing CT.

5.b. What do you mean by shunts and multipliers and derive the expression for shunt and multipliers.

6.a. Discuss how the iron losses are measured by using Wattmeter.

6.b. List advantages of instruments transformers.

6.c. Discuss how leakage flux is measured.

7.a. List advantages of electronic meters over the conventional meters.

7.b. Discuss construction and operation of TRUE RMS reading voltmeter.

7.c. List characteristics of DVM and explain successive approximation type DVM.

8.a. Explain the principle of operation Q meter and discuss different application of Q-meter.

8.b. List different types of DVM. Explain with sketch the Ramp type DVM.

9.a. Explain why recorders are essential? With sketch explain x - y recorder.

9.b. Discuss with necessary figure

1. ECG
2. EEG.

10.a. Write a short note on

1. LED
2. Nixie tube
3. LCD.

10.b. With neat sketch explain LVDT recorder.

10.c. Write a short note on dot matrix display.