In the world of Electronics, as in the Real World, there are those who try to manipulate the truth to take advantage of those who have a limited understanding of its underlying principles.\u00a0 We will call these manipulators scammers.<\/p>\n
One scam that I often see is when an experimenter tries to get a LED circuit running and tells everyone that it’s brighter than before.\u00a0 The presenter says that it’s brighter, but gives no quantitative measurement, only that it looks brighter.\u00a0 Without a measurement, his brightness claim is nothing more than an opinion, with no basis in fact.\u00a0 It is up ti the person making the claim to provide evidence that what he is claiming is true and more than just an opinion without any factual basis.<\/p>\n
If a project has claims of a certain performance, then it is logical that the performance should be documented.\u00a0 A measurement of light output of the LED would give a relative indication of performance.\u00a0 Light meters, or luxmeters, are inexpensive, less than $50 with shipping.\u00a0 Provided that the LED is kept the same distance from the sensor, the luxmeter will give a reasonably accurate indication of the light output of the LED as the circuit is adjusted.<\/p>\n
Those who have little experience in this field should always remember that what people say and what the actual truth is have little relation to each other.\u00a0 If someone makes a claim, the first thing that the viewer should ask is what is the claim based on?\u00a0 Is it just a statement of opinion, with no evidence that is proof?\u00a0 If so, then do not accept it as being true.<\/p>\n
In this case of the claim that “it’s brighter”, the guesstimate is being made by the claimant’s eyes.\u00a0 The eye can be very deceptive.\u00a0 When the person is in a bright area, a fairly bright LED can look dim.\u00a0 One good example is when you try to view your cell phone screen outside and it looks so dim you can barely read it.\u00a0 You have to go inside to let your eyes open up so that more of the cell phone’s light gets in.\u00a0 What this means is that your eye is a very poor judge of brightness because the pupil of your eye adjusts automatically and you have no indication of how it’s limiting the light.\u00a0 In one bright area you would make a judgment that the LED is dim, but in a darker area you might judge the LED as bright.\u00a0 So the Number 1 Rule<\/em> is to never trust your eye’s judgment on how bright something is.<\/p>\n Parts – They’re important<\/strong>\u00a0 Do you understand what your components are doing, and do you know if you are subjecting them to stresses outside of their rated limits?\u00a0 If you are, do you have a way to test them to see if their performance is still normal?\u00a0 A mountain climber doesn’t use a frayed rope.\u00a0 But in the case of an electronic component, one may seldom see the effects of use and abuse.\u00a0 If you don’t have a way to test them, then you should be stocking new and unused ones that have not yet been through the mill.\u00a0 Transistors are cheap, only a few pennies apiece.\u00a0 It’s foolish and futile to try to get a circuit working when a 4 cent transistor that has been abused is the problem causing the trouble.<\/p>\n I must say a word about the parts and their suppliers.<\/strong><\/p>\n If you get parts from a reputable distributor you can be reasonably certain that the parts are new, prime parts without any “seconds” that may be out of tolerance.\u00a0 If you buy from some distributors, you may not have a choice of selecting a better grade of component.\u00a0 For instance, if you buy a BC337-25 transistor from Digi-Key or Mouser, you are ordering that exact transistor with the gain range of -25 specified.\u00a0 If you order a BC337 from Futurlec, they may not have any gain range suffix, so you will not know what the gain of the transistors you receive are.\u00a0 They could be evenly distributed throughout the gain ranges, which means you could measure the gain and select the higher ones for your use.\u00a0 This could save you some small amount of money, but when Avnet charges $2.28<\/a> for a hundred BC337-40s, and Futurlec charges $7.00 for the plain BC337<\/a>, it really makes no economic sense.<\/p>\n Surplus dealers are a whole ‘nother story and run the gamut from new, never used parts in their unopened packages, to cannibalized parts removed from old equipment.\u00a0\u00a0 The cannibalized parts at first seem to be the worst choice, but that may not be true, I’ll explain.\u00a0 With cannibalized parts, you are not deceived: you know ahead of time that you’re getting used parts.\u00a0 In some cases, the part may have a lifetime associated with its use so the older it is, the less life it may have left.\u00a0 But if you can’t find it in better condition, this may be the only choice.\u00a0 In other cases, when the part such as a transistor has been used within its rated maximums, can continue to be used with full performance and no degradation for decades to come.<\/p>\n On the other hand, there are those parts that may have made it through the production line, but my be out of tolerance or what they call ‘seconds’.\u00a0 Here is a part that may look new, and may be sold as new, but is not capable of performing as a new part.\u00a0 The new look allows the seller to deceive the buyer and get premium prices for an inferior part.\u00a0 This often happens with electronic parts because the electrical and electronic qualities of the part may only be found with test equipment that the average buyer does not have.\u00a0 Thus the average buyer may never know that he or she has bought substandard parts.<\/p>\n There is another category of parts that has been found, counterfeit parts.\u00a0 With transistors, especially power transistors, the counterfeiter rubs off the original markings and puts on the markings of a higher performing power transistor.\u00a0 The buyer gets stuck with a substandard part that may fail due to its inadequacy.\u00a0 And you might think these don’t get into the mainstream market, but you could be wrong.\u00a0 Some otherwise reputable distributors get stuck with these dud parts even when they believe they are getting prime parts.\u00a0 But the chances are far less than if the buyer were to get the parts from a shady dealer.<\/p>\n All together, the parts that buyers receive can determine the fate of the product they go into.\u00a0 If the experimenter buys a low grade part, it may not effect the outcome of the equipment as much.\u00a0 Yhe experimenter may find that the part is not giving the performance that was expected.\u00a0 A high volume producer may have hundreds or thousands of the product sold and in service when it is discovered that the product has defective parts.\u00a0 This happened several years ago when, among other PC makers, Dell made GX-270 computers<\/a> with electrolytic capacitors that were defective, and started to fail after a year or so.\u00a0 It cost the company a lot of money – $300 million US – and hurt their reputation.<\/p>\n","protected":false},"excerpt":{"rendered":" In the world of Electronics, as in the Real World, there are those who try to manipulate the truth to take advantage of those who have a limited understanding of its underlying principles.\u00a0 We will call these manipulators scammers. One scam that I often see is when an experimenter tries to get a LED circuit <\/p>\n (Read More…)<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,12,13,17],"tags":[],"class_list":["post-1237","post","type-post","status-publish","format-standard","hentry","category-electronics","category-led","category-lighting","category-meters-and-test-equipment"],"_links":{"self":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/1237","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1237"}],"version-history":[{"count":16,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/1237\/revisions"}],"predecessor-version":[{"id":1764,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/1237\/revisions\/1764"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1237"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1237"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1237"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}