electrical related

Discussion in 'General Electronics Chat' started by aanchal, Jan 14, 2008.

  1. aanchal

    Thread Starter Member

    Jan 10, 2008
    11
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    can we guess/determine the size of a 3ampere commercially available thyristor
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    You mean just by looking at it?

    If it's commercially available, it will have a number on the case that will ley you obtain a spec sheet that will tell you all the SCR's parameters. Even if you guess correctly about the current capacity, it will still fail if you put it in a circuit where the voltage is higher than the junctions will withstand.
     
  3. aanchal

    Thread Starter Member

    Jan 10, 2008
    11
    0
    i dont hav to guess bout the current capacity,what i require is a 3 ampere thyristor,i jst want to have an idea of its size,is it anywhere related,or can it b guessed by general experience.
     
  4. nanovate

    Distinguished Member

    May 7, 2007
    665
    1
    I could be wrong here, but you could look up some 3A thyristors and see what what packages they come in.
     
  5. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
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    The problem is that a 3A thyristor and a 1A thyristor may have the same package (say T0-220), so they will be equal in size. In that case, what makes them different are they internals: basically, the 3A device will probably have a bigger chip and perhaps a smaller case to junction temperature (typically 5ºC/W to 3ºC/W in TO-220 packages).
     
  6. thingmaker3

    Retired Moderator

    May 16, 2005
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  7. nomurphy

    AAC Fanatic!

    Aug 8, 2005
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    The specs for a TO-220 case is not necessarily the dimensions for a 3 amp SCR. It could be in TO-3 case, a TO-92 case, or some surface-mount variation.

    You need to search manufacturers' websites (such as Fairchild or On-Semi) for an SCR or Triac that fits your electrical requirements, and this will determine it's package size per the manufacturer (one may supply it in a TO-3 and another in a TO-92).
     
  8. thingmaker3

    Retired Moderator

    May 16, 2005
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    3 Amp SCR in a TO-92? Impressive!

    I suppose one might find a 3A in a TO-3.
     
  9. beenthere

    Retired Moderator

    Apr 20, 2004
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    Perhaps as small as TO-39.
     
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