BIEL-029 No. of Printed Pages : 5

DIPLOMA - VIEP - ELECTRONICS AND COMMUNICATION ENGINEERING (DECVI) /

ADVANCED LEVEL CERTIFICATE COURSE IN ELECTRONICS AND COMMUNICATION

ENGINEERING (ACECVI)

Term-End Examination

June, 2017

BIEL-029 : ELECTRONIC MEASUREMENT AND INSTRUMENTS

Time : 2 hours Maximum Marks : 70

Note : Attempt five questions in all. Question no. 1 is

compulsory. All questions carry equal marks.

Missing data, if any, may be assumed. Use of

scientific calculator is allowed.

1. Choose the correct answer from the four

alternatives : 7x2=14

(a) Errors due to human mistakes are called

(i) Systematic Errors

(ii) Instrument Errors

(iii) Gross Errors

(iv) Environmental Errors

BI EL-029

1 P.T.O.

(b) Moving iron and PMMC instruments can be distinguished from each other by looking at the

(i) Pointer

(ii) Terminal Size

(iii) Scale

(iv) Scale Range

(c) Which type of method of focusing is used by CRT in CRO ?

(i) Electrostatic

(ii) Electromagnetic

(iii) Electromechanical

(iv) None of the above

(d) A digital voltmeter uses an A/D converter which needs a start pulse, uses an analog comparator and has a relatively fixed conversion time independent of the applied voltage. The A/D converter is

(i) a Successive Approximation Converter

(ii) a Digital Ramp Converter

(iii) a Dual Slope Converter

(iv) All the above

(e) In CRO, which of the following is not a part of the electron gun ?

(i) Cathode

(ii) Grid

(iii) Accelerating plates

(iv) X-Y plates

BIEL-029 2

(f) A spring controlled moving iron instrument

exhibits a square law response resulting in a

non-linear scale. The shape of the scale can

be made almost linear by

(i) keeping rate of change of inductance

L, with deflection 0, as constant.

(ii) keeping –1

' d0j as constant.

0

(iii) keeping —1

as constant, where k is k0

the spring constant.

dL (iv) keeping 0 . — as constant.

d0

(g) The difference between the Spectrum

Analyser (SA) and CRO is

(i) CRO and SA both measure time

domain signal.

(ii) CRO and SA both measure frequency

domain signal.

(iii) CRO measures time domain signal

and SA measures frequency domain

signal.

(iv) CRO measures frequency domain

signal and SA measures time domain

signal.

BIEL-029

3 P.T.O.

2. (a) Explain various static and dynamic

characteristics of instruments. 10

(b) A 600 V voltmeter is specified to be

accurate within ± 2.5% at Full Scale

Deflection (FSD). Calculate the limiting

error when the instrument is used to

measure a voltage of 400 V. 4

3. (a) Explain why PMMC instruments are most

widely used. Discuss their advantages and

disadvantages. 7

(b) Describe the working of an analog AC

ammeter and voltmeter.

4. (a) Define the sensitivity and deflection factor

of a Cathode Ray Tube (CRT). What are the

roles of the following in a CRO ?

7

(i) Time Based Generator Circuit

(ii) X-Channel

(iii) Triggered Sweep

(iv) Astigmatism

(b) Differentiate between a Double Beam CRO

and Dual Trace CRO in detail. 7

BIEL-029 4

. (a) Draw the block diagram and working of an

integrating type Digital Voltmeter (DVM). 7

(b) An integrator has 100 kQ and 11./F

capacitor. If the voltage applied to the

integrator input is 1 V, find the voltage

developed at the output after 1 sec. If the

reference voltage applied to the integrator

at time t 1 is 5 V, find the time interval

of t2 .

t 1 --> rise time of reference voltage waveform

at the output of the integrator

t2 —> fall time of reference voltage waveform 7

6. (a) Explain with a neat diagram, the working

of a pulse generator. 7

(b) Draw the block diagram of a 'Digital phase

meter'. Also, explain its working operation. 7

7. Write short notes on any two of the following : 2x7=14

(a) Spectrum Analyzer

(b) Grounding

(c) Q-Meter

BIEL-029

5 1,000