electrical related

Thread Starter

aanchal

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

beenthere

Joined Apr 20, 2004
15,808
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.
 

Thread Starter

aanchal

Joined Jan 10, 2008
11
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.
 

nanovate

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

bloguetronica

Joined Apr 27, 2007
1,359
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).
 

nomurphy

Joined Aug 8, 2005
567
can we guess/determine the size of a 3 ampere commercially available thyristor
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).
 
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