Chapter 1 Introduction

Objectives Units of measurement SI system Powers-of-ten notation Scientific and engineering notations Symbols used in text

The Electrical/Electronics Industry The reduction in size of virtually all electronic devices is due to advances in integrated circuit (IC) development The Pentium-4 has 42 million transistors in an area measuring only 0.34 square inches

The Electrical/Electronics Industry With all of the advancements in electronics, once the fundamental equations are understood, they will not be replaced by other equations as more advanced theory is considered

Units of Measurement Before substituting numerical values into an equation, be sure of the following: each quantity has the proper unit of measurement as defined by the equation the proper magnitude of each quantity, as determined by the defining equation, is substituted each quantity is in the same system of units (or as defined by the equation)

Units of Measurement the magnitude of the result is of a reasonable nature when compared to the level of the substituted quantities the proper unit of measurement is applied to the result

Systems of Units In 1960, the International Bureau of Weights and Measures adopted the SI (System International) system of units The SI system was adopted by the Institute of Electrical and Electronic Engineers (IEEE) in 1965 This book uses all major units and abbreviations of the SI system

Powers of Ten 1 = 100 10 = 101 100 = 102 1000 = 103 numbers greater than 1 have positive powers 1/10 = 0.1 = 10-1 1/100 = 0.01 = 10-2 1/1000 = 0.001 = 10-3 1/10000 = 0.0001 = 10-4 numbers less than 1 have negative powers

Powers of Ten When adding or subtracting numbers in a powers-of- ten format, be sure that the power of ten is the same for each number Separate the multipliers, perform the required operation, and apply the same power of ten to the result

(A X 10n)(B X 10m) = (A)(B) X 10n+m Powers of Ten When multiplying numbers in powers-of-ten format, first find the product of the multipliers and then determine the power of ten for the result by adding the power of ten exponents (A X 10n)(B X 10m) = (A)(B) X 10n+m

Powers of Ten When dividing numbers in the powers-of-ten format, first find the result of dividing the multipliers, then determine the associated power for the result by subtracting the power of ten of the denominator from the power of ten of the numerator (A X 10n)/(B X 10m) = A/B X 10n-m

Powers of Ten When finding the power of a number in the powers- of-ten format, first separate the multiplier from the power of ten and determine each separately Determine the power of ten component by multiplying the power of ten by the power to be determined (A X 10n)m = Am X 10nm

Powers of Ten Scientific notation and engineering notation make use of powers of ten Scientific notation requires that the decimal point appear directly after the first digit greater than or equal to 1 but less than 10. A power of ten will appear with the number Engineering notation requires that all powers of ten must be multiples of 3, and the mantissa must be greater than or equal to 1 but less than 1000

Powers of Ten

Conversion Between Levels of Powers of Ten It is often necessary to convert from one power of ten to another For instance it may be necessary to convert a reading in kilohertz (kHz) to a corresponding value in megahertz (MHz) An increase or a decrease in the power of ten must be associated with the opposite effect on the multiplying factor

Conversion Within and Between Systems of Units Set up the conversion factor to form a numerical value of (1) with the unit of measurement to be removed from the original quantity in the denominator Perform the required mathematics to obtain the proper magnitude for the remaining unit of measurement

Symbols

Activity 1 Try to do the conversion 0.03 h to seconds 1000 mm to meters Find the distance in meters that a mass travelling at 600 cm/s will cover in 0.016h. After 10 minutes, discuss with your partners besides you. Volunteer to present the answers Give yourself a mark with max of 5 and submit to your lecturer.

Summary A unit of measurement must be applied to any result to give it full meaning SI is the system of units applied to the electrical/electronics industry Powers of ten are employed to make it easier to work with the very small and large numbers that we encounter in the electrical/electronics industry We will encounter values expressed in Scientific and Engineering notation

Summary When converting from one power of ten to another, remember that if the power increases, the multiplier decreases, and vice-versa When using calculators, always check to make sure that the result makes sense With computers, whenever a software program is available that can perform the operations you require, it is usually wise to use the program rather than try to write your own program