Reading Resistor Chart Values - The Learning Circuit

the following program is brought to you by element14 the electronic design community where you can connect and collaborate with top engineers from around the world join now at element14.com welcome back to the learning circuit I'm Karen and today we're gonna learn how to read resistor values many electrical components are marked with their values but since parts can get quite small and numbers can get quite large sometimes those values are written in a code before we try to understand those codes let's look at how we determine how many zeros are in a number by understanding the prefixes used in electronics here's a chart for the names of the prefixes used in the metric system in reference to electrical components the most commonly used prefixes are kilo and mega for whole numbers and milli micro nano and Pico for decimals you'll notice the powers of those numbers are all multiples of 3 values get abbreviated by shifting the decimal place over by those multiples of 3 for resistors we mostly use kilo and mega here is a list of standard resistor values compare the abbreviated numbers to those on the prefix chart our resistor that is 4700 ohms is called 4.7 K ohms or kilo ohms a 100,000 ohm resistor is 100 kilo ohms a 1 million ohm resistor is 1 mega ohm [Music] there are through-hole resistors and surface mount resistors through all resistors have colored bands on them resistors use a color coding system to indicate their value as well as their tolerance as we learned in the resistor episode tolerance is the accuracy or margin of error of the resistor rating ranging anywhere from a fraction of a percent up to 20 percent here is the color code chart black brown then the colors in order of the rainbow red orange yellow green blue violet followed by gray and whites followed by gold and silver we can use this chart to determine the digit multiplier or tolerance that the color band represents resistors can have a varying number of bands on them will focus on four and five band resistors as they are the most common on a four band resistor the first two stripes are combined together to form a number between 1 and 99 the third stripe is the multiplier and the last marks the tolerance on a 5 band resistor the first three stripes get read as a single number while the fourth stripe is the multiplier and the fifth band represents the tolerance most five band resistors are precision resistors with tolerances of one percent or two percent indicated by a brown or red band on the far right while most of the four band resistors have tolerances of five percent or ten percent indicated by a gold or silver band if the resistor has no fourth tolerance band then the default tolerance would be twenty percent there are resistors with a single black bands these are zero ohm resistors since they have the same packages other resistors they can easily be placed on a PCB by automated machines they're often used as wire simply just to connect traces let's look at some four and five band resistors and figure out their values here are 100 ohm resistors the four band is brown black brown the five band is brown black black black here are 330 ohm resistors the four band is orange orange brown the five band is orange orange black black here are four point 7 kilo ohm resistors the four band is yellow purple red the five band is yellow purple black brown here are 10 kilo ohm resistors the four-band is brown black orange and the 5 band is brown black black red and lastly here is a 220 kiloohm resistor the 4 band is red red yellow while the 5 band is red red black orange notice that with each pair the first 2 stripes are the same colors while the third and fourth stripes change to account for the amount of zeros needed while banded through hole resistors are color-coded surface mount resistors are instead marked by a short series of numbers and letters usually three or four their coding is similar to that of banded resistors where the first two digits are significant and the last digit represents the multiplier let's take a look at a few here is an SMD resistors labeled 5 1 0 the first 2 digits are significant and the third digit indicates how many zeros to add this resistor says 5 one with no zeros added making it a 51 ohm resistor a resistor labeled 101 equals 10 plus one zero and is a 100 ohm resistor here is a chart with more three digit codes with their values the last digit tells you how many zeros to add 2 to 2 equals 22 plus 2 zeros which equals two thousand and two hundred which is two point two kilo ohms 103 equals 10 plus three zeros which is ten thousand which is ten kilo ohms three oh five is 30 plus five zeros which is three million three mega ohms here is a chart of four digit codes as you can see on this chart the third number on nearly all four digit resistors is zero let's put the two charts side-by-side and compare for a two kiloohm resistor the three digit code is 202 while the four digit code is two zero zero one for a thirty six kiloohm resistor the three digit code is three six three while the four digit code is three six - for a 2 mega ohm resistor the three-digit code is 2:05 while the 4 digit code is 2 0 0 for some surface mount resistors come in values that include a decimal such as 0.33 ohms or four point seven ohms decimals can be difficult to read if a resistor gets old or dirty so an R is used in place of the decimal here's a chart with resistor codes that use our note that are can be before the number like our 33 which is 0.33 ohms or in the middle of the number like 2 R for 2 point 4 ohms notice that in 4 digit codes the arc can be the third digit indicating that the first two digits are the true value of the resistor 75 r0 is 75 point 0 which is 75 ohms when shopping for surface mount resistors you may see some other codes in the item description here's a chart of some of the series of letters you may see the most common you'll see in here are SMD for surface mount device and SMT for surface mount technology you may also see a number representing the size for the resistor here are the Imperial and metric codes for the various surface mount resistor sizes the codes are named for the length and width of the resistor inches in imperial and millimeters in metric today we covered how to read resistor codes to learn the values of resistors if you have any questions or comments about resistor codes please post them on the element14 community on element14.com /the learning circuit happy learning [Music]

Channel: element14 presents

Views: 108,397

Keywords: electronics, hardware, gaming, hacking, mods, weekly, element14, tbhs, benheck, madison, wisconsin, maker, engineering, through hole resistors, surface mount resistors, the learning circuit, PCB, element14 presents, passive components

Id: BRHn8Z2P9y8

Length: 7min 38sec (458 seconds)

Published: Wed Sep 05 2018