Punjab Engineering College 2005 B.Tech Electronic Measurement & Instrumentation - Question Paper

EC 307 fifth Sem May 2005
ELECTRONIC MEASUREMENT & INSTRUMENTATION

Max Marks 60
Max Time three Hours

Note: part A is compulsory. Attempt any 4 ques. from part B and 2 from part C.
Make necessary assumptions wherever needed.

part A Marks two every

1.
(10*2=20)
(a) What precautions must be taken when using a sampling oscilloscope?
(b) elaborate the advantages of dual trace over dual beam for multiple-trace oscilloscopes?
(c) What is Harmonic Distortion?
(d) What is the dynamic range of a spectrum analyser with a third-order intercept point of +25 dBm and a noise level of -85 dBm?
(e) elaborate the important functions performed by instrument transformers?
(f) Why is sensitivity of the a.c. scales of a multimeter less than the d.c. section?
(g) What is strain gauge? Name 4 resistance materials for use in wire and foil gauges.
(h) Compare LED and LCD in respect of:

(i) construction materials
(ii) construction principle

(i) elaborate the advantages and disadvantages of piezoelectric transducer?
(j) elaborate the various methods of data transmission?

part B Marks five every
(5*4=20)
2. define with diagrams the construction of an LVDT and discuss its working principle.

3. How does the digital storage oscilloscope differ from the conventional storage oscilloscope using a storage cathode ray tube? elaborate the advantages of each?

4. calculate the value of self-capacitance of a coil when the subsequent measurements were made. At frequency f1= two MHz the tuning capacitor is set at 450 p.f. When the frequency is increased to five MHz, the tuning capacitor is tuned at 60 p.f.

5. If a digitizing oscilloscope is to have a 6-bit resolution in both the horizontal and vertical axes and is to display transients at a rate of one ms per division for a display of 10 divisions, what is the speed needed of the input A/D converter?

6. give a comparison ranging from hydraulic and pneumatic transmission and provide applications of every. Suggest other methods of transmission along with their advantages over these 2 methods.

part C Marks 10 every
(10*2=20)
7. elaborate the typical operating and performance characteristics of digital voltmeters? How are digital voltmeters classified? provide the block diagram of a staircase-ramp digital voltmeter and discuss its working.

8. (a) What is gauge factor? A resistance strain gauge with a gauge factor of two is fastened to a member which is subjected to a strain of one x 10-6. If the original resistance value of the gauge is 130, compute the change in resistance.
(b) provide the functional block diagram of the heterodyning wave analyzer and discuss its working.

9. discuss the working of an X-Y recorder with the help of a diagram. elaborate the important features of this instrument?

Earning:   Approval pending.