Measurements and Instrumentation

CHAPTER - 5

MEASUREMENTS AND INSTRUMENTATION

1. INTRODUCTION

Measurements:

The measurement of a given quantity is essentially an act or the result of comparison between the quantity (whose magnitude is unknown) & a predefined standard. Since two quantities are compared, the result is expressed in numerical values.

Basic Requirements of Measurement :

1. The standard used for comparison purposes must be accurately defined & should be commonly accepted.

2. The standard must be of the same character as the measurand.

3. The apparatus used & the method adopted must be provable.

Measuring Instrument :

It may be defined as a device for determining the value or magnitude of a quantity or variable.

Electronic Instrument:

An electronic instrument is the one which is based on electronic or electrical principles for its measurement function. The measurement of any electronic or electrical quantity or variable is termed as an electronic measurement.

Advantages of Electronic Measurement

The advantages of an electronic measurement are

1. Most of the quantities can be converted by transducers into the electrical or electronic signals.

2. An electrical or electronic signal can be amplified, filtered, multiplexed, sampled and measured.

3. The measurement can easily be obtained in or converted into digital form for automatic analysis and recording.

4 The measured signals can be transmitted over long distances with the help of cables or radio links, without any loss of information.

5. Electronic circuits can detect and amplify very weak signals and can measure the events of very short duration as well.

6. Higher sensitivity, low power consumption and a higher degree of reliability are the important features of electronic instruments and measurements.