5Prefixes How many meters are there in a kilometer? 1000How many milliseconds are there in a second?How many bytes are there in a Gigabyte?1,000,000,000
6Prefixes (cont.) Kilo, milli, and Giga are all called prefixes. Can you guess why they call them prefixes?Because they come before the unit such as millisecond.Prefixes are used to represent how much of the particular unit is being represented
7Prefixes we’ll use in Elec50A Abbrev.ExampleWhat it meansScientific NotationGigaGGmx1,000,000,000x109MegaMMVx1,000,000x106KilokkAx1,000x103Unit Base-Sx1x100Millimmgx.001x10-3Micro Or uuΩxx10-6Nanonnsxx10-9PicoppAxx10-12
8In your book they show other prefixes we won’t use much if at all.
9Quick Prefix Quiz How seconds are there in a Gs? 1 billionHow many volts in a mV?.001How many mV in a volt?1000How many amps in a kiloAmp (kA)?
10Quick Prefix Quiz (cont.) How small is a nA1 billionth or A or 10-9How small is a uΩ?1 millionth or Ω or 10-6How big is a pV?1 trillionth of a volt or V
113 ways to write a numberRegular Way Using Prefixes Scientific Notation1 million volts 1 thousandth of an amp 1 millionth of an ohm 1 billion grams 5 thousand meters 1 second1,000,000 V.001 AΩ1,000,000,000 g5000 m1 s1MV1mA1uΩ1Gg5km1s1x106 V1x10-3 A1x10-6 Ω1x109 g5x103 m1x100 sNotice that the prefixes take place of the scientific notation and everything else stays the same. Meaning –k = x103
12Write the following in scientific notation: 3mV18kV43ms2.1GA30uA57ps3x10-3V18x103V43x10-3s2.1x109A30x10-6A57x10-12s
13Write the following using prefixes Notice “m” replaced all of “x10-3” and everything else stayed the same483x10-3A32x106V2x10-9A3.4x10-12s.350x103Ω42x10-6V483mA32MV2nA3.4ps.350kΩ42uVThis can be simplified to just 350 Ω
14More practice problems - Converting regular numbers to scientific notation. Convert 4578 to scientific notationConvert to scientific notationConvert 4.56 to scientific notationWhat does 6.4 x 10^0 = ?4.578 x 1039x10-54.56x1006.4 x 1 = 6.4Notice in the above example 9x10-5 cannot be converted to a prefix very easily because there is no prefix for -5. So it is useful to convert this number to one that does have a prefix.9x10-5 = = = 90 x 10-6 = 90uWhat we just did was convert scientific notation to engineering notation!!! (Go ahead and write home)
15So what is the difference between scientific notation and engineering notation? In scientific notation there is always only one digit or number in front of the decimal and everything else is behind the decimal.Ex: 9.54 x 10-5In Engineering notation the exponent is always a multiple of 3.Ex: 95.4 x 10-6Notice -6 is a multiple of 3
16Notice all prefixes are multiples of 3 Abbrev.ExampleWhat it meansScientific NotationGigaGGmx1,000,000,000x109MegaMMVx1,000,000x106KilokkAx1,000x103Unit Base-Sx1x100Millimmgx.001x10-3Micro Or uuΩxx10-6Nanonnsxx10-9PicoppAxx10-12
17We will be using engineering notation for electronics courses because it is useful in converting to prefixes.Convert the following to engineering notation and then to its corresponding prefix.00043A23x10-2V67x107sm= 430 x 10-6A = 430uA= .23V = 230x10-3V = 230mV= s = 670x106s = 670Ms= 7.83x10-9s = 7.83nm
19Get out your Calulators First put your calculator in Engineering NotationPress 2nd FPress SET UPPress 1 for FSE (Fixed Scientific EngineeringPress 2 for Engineering NotationEnter 9 so it shows the most amount of precisionIt says ENG on the left side of the screen now.If you ever want your calculator to show normal looking numbers as answers again, you’ll have to go through this process and press 0 for fixed numbers at the last step.
20Enter and press =.Notice it automatically put it into Engineering Notation.It shows 567E3E is an abbreviated way of saying “x10^”567E3 = 567 x103Now press and press enterYou may need to press the Change button to convert it from a fractionIt shows 400E-9.Convert this to a prefix400n!!!!
21Look on Page 21 of your book Throughout the text book, anytime we will encounter a new feature using the calculator, it will tell you the buttons to press to perform the particular operation.
22Convert to a prefix using calculator 4300Ω.00076s= 56uV= 5.43MA= 4.3kΩ= 760us
23Using a Calculator for this stuff 3 ways to enter these numbers Entering 5.4x103Just enter 54005.4xis the same thing as “x10^”Sometimes 5.4x103 can be expressed as 5.4E3.This is the same thing as 5.4 EXP 310xEXP
24Converting between units Many times it is useful to convert from one prefix to another. ie: uA to nAConvert 43uA to nA43uA = 43000nATo do this we will use 2 rules. WRITE THESE DOWN!If you are going from a larger exponent to a smaller exponent, then you move the decimal to the rightIf you are going from a smaller exponent to a larger exponent, then you move the decimal to the left
25Convert 43 mV into _______uV .043V Convert 14kV into ________MV - If you are going from a larger exponent to a smaller exponent, then you move the decimal to the right. - If you are going from a smaller exponent to a larger exponent, then you move the decimal to the left43Convert 43 mV into _______uV.043VConvert 14kV into ________MVConvert 72GV into _______nV43.uV = 43uV.01472,000,000,000,000,000,000V
26- If you are going from a larger exponent to a smaller exponent, then you move the decimal to the right. - If you are going from a smaller exponent to a larger exponent, then you move the decimal to the leftNow convert to Engineering Notation1010x103A1.51.5x106Ω1.21.2x103Hz51005100 x10-6A0.040.04x10-3A11x103W15001500x10-12F.15.15x103V.25.25x106W37003700x103Ω
27Using the table. You have this as a handout Convert 1 microsecond into ________secondsConvert nanoseconds into ________microsecondsConvert .4 milliohms into __________ ohms2.8345.0004
28Explaining Handout – This handout may be used on tests, but no writing may be on it.
29Units Worksheet Lets do together 1, 2, 10, 11, 17, 22 Go ahead and finish the rest of the worksheet on your own. If you don’t finish it in class it is homework.Its due on Monday