Why electronics components have secret codes? (LM7805 for Volt Regulator)

Discussion in 'General Electronics Chat' started by coffeemani, Feb 26, 2016.

  1. coffeemani

    Thread Starter New Member

    Feb 26, 2016
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    Why electronics components have secret codes? Like LM7805 for Volt Regulator. I am new in electronics and I want to create some circuit designs in softwares like Circuitmaker, Multisim, Qucs or Proteus. I do understand the symbols of components and simple names like diode or resister but I am not able to understand how a simple diode gets a complex name like 1N5349B ?? Is there anyway to understand to read this (1N5349B) and figure out that if its a diode or a transformer or a resistor??
     
  2. SLK001

    Well-Known Member

    Nov 29, 2011
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    Look at the manufacturer's data sheet. It will usually explain the markings on the device. There are usually no secret codes - just knowledge not yet understood.
     
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  3. bertus

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  4. Dodgydave

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    They don't have secret codes, each manufacturer has their own id markings, like LT, LM, ST,TI, Max, etc, you just have to look it up on google. After a while you know what they are, it takes years of practice and learning.
     
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  5. #12

    Expert

    Nov 30, 2010
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    Everything has to have a name. There are so many bleeping thousands of parts that English words are not practical.
    1N means it is a one junction device as in, not a transistor. 53 describes the size. 49 describes the voltage. B describes the accuracy.
    LM means Linear Monolithic. 05 is the voltage.

    here, try this:http://datasheetcatalog.com/

    Eventually you will have a catalog in your head. Like a doctor knows an ossa from a fossa, we know part numbers.
     
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  6. Evanguy

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    Dec 21, 2014
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    Why does toyota call their cars "corolla" and "yaris" why not just call them car and car.


    The names of the components are named like that so you can tell them apart. and there are different series parts. so they may have the same prefix but different following number/letters,
    ie, lm7805 and lm7815 they are both part of the lm78 series of voltage regulators, the last number are their output voltage so the example is a 5v reg and 15v reg of the LM78 regulator series there are other types of voltage regulators too, so if i said 15v regular you may thing zener diode if i didn't tell you what i was looking for
     
    Last edited: Feb 26, 2016
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  7. ian field

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    Oct 27, 2012
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    Russian parts have even more secret codes unless you can read Cyrillic characters.
     
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  8. ian field

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    Best not to overlook "house coded" parts - those actually are secret codes.
     
  9. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    The secret codes on part numbers are very similar to the secret codes of telephone numbers: sure they exist, but there is absolutely no need to learn them just to make a phone call.
     
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  10. WBahn

    Moderator

    Mar 31, 2012
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    For the most part, there is nothing secret about them. They generally fall into to categories -- industry-established codes that most manufacturers adhere to and manufacturer codes in which a given manufacturer comes up with their own part numbers and which few, if any, other manufacturers attempt to conform to.

    There is no overall system to part numbers, so it is virtually impossible to just be given a part number and be able to figure out what it is (of course, with the internet, this is not really the case and if you just enter the part number into Google you will almost always get a relevant hit on the first page). But if you know what the general type of component that the device is, then you can start making pretty good guesses. For instance, if you know that it is a voltage regulator and the part has 7805 in it, then the 78 tells you that it is a fixed-output positive voltage regulator and that the output is +5 V. While if it is 7912 then the 79 tells you that it is a fixed output negative voltage regulator and the output is -12 V.

    For diodes and transistors, the part numbering scheme became fairly standardized around the 1n... and 2n... part numbers. But even so, while there are subsets of part numbers in which the numbers have actual meaning, for the most part it is just an entry into a dictionary of parts that have certain characteristics.

    Many part numbers don't have any particular systematic encoding, they are simply the part number that was assigned to that part by the first manufacturer that marketed it and, as other manufacturers started marketing compatible parts, they often wanted to use the same core part number so that users would more easily associated their part as an alternative to the original manufacturer's part. For instance, the 555 timer was originally called that because the folks at Signetics thought that the three 5 kΩ resisitors that formed it's voltage divider tree were significant enough to warrant recognition in the name. There was nothing systematic about it. The 556 timer is just an IC with two 555 timers in it. But the timer became extremely successful and to this day lots of different manufacturers make variants of 555 and 556 timers and use those numbers as the core of their part numbers.
     
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  11. SLK001

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    Nov 29, 2011
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    Not if you can get the manufacturer's data sheet! But you're right, house coded parts are secret for a reason - either to keep someone from repairing them, or to prevent someone from copying their design.
     
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  12. GopherT

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    Because it was really hard to read the small type on a diode when they were printing the full name on each piece. Imagine when we had to read: "silicon diode with 75 volt, 100 mIlliamp, 10 nanoSecond recovery time" all on the little glass diode. Granted, it got better when they abbreviated milliamps with mA and nanosecond with nS but still, that only made the font a few tenths bigger. Now they make it so big that they need two (some brands three) lines to type 1N4148 on a diode.
     
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  13. Papabravo

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    I guess the marking system for surface mount components would be enough to make your head explode, but the reasons are largely a matter of how many characters of what size can be printed on tiny components. One of the ASICS that I helped to develop has all of the developers names on the metalization mask, but they are so tiny you can't read them without a microscope.
     
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  14. ian field

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    Found a funny anecdote years ago; someone at a micro manufacturer masked a picture of Mickey Mouse on a MCU substrate - apparently Disney found out and sued for infringement.
     
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  15. GopherT

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    Mostek 5017 alarm clock chip, there are likely others.

    A long list of novelties found by Florida State crew...

    http://micro.magnet.fsu.edu/creatures/


    image.jpg
     
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  16. ErnieM

    AAC Fanatic!

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    Back in the 80's I would always add circles around lettered test points, first for clarity to distinguish them, and next to make it easy to add one of these into a government system:

    [​IMG]
     
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  17. AnalogKid

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    Many chip makers embed art in the fringes of the chip masks. Precision Monolithics once put teeth, a heart, and a competitors logo on a high precision A/D: eat your heart out, Analog Devices.
     
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  18. RichardO

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    My recollection of the story was that the design was presented at a semiconductor conference and engineers from Analog Devices said it could not be done. The desigineers added the "art" to the die in responce saying that they would remove it if they were proven wrong. I don't think it was ever removed.
     
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  19. coffeemani

    Thread Starter New Member

    Feb 26, 2016
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    Thank you Guys!!
     
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