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flotulopex
- 3rd November 2008, 10:40
Hello,

Is there any "rule of thumb" or simple way to calculate a triac's power dissipation?

I'm trying to build-up a simple micro-controlled 230VAC light switch for incandescent bulbs (purely ohmic) and I would prefer to understand how to correctly choose a triac instead of just taking the ones proposed in the examples one can find in the internet.

As far as I could find information up to now, it looks to be necessary to use the graphs provided in some datasheets to determine each triac's power dissipation.

But one can't read every datasheet to find out the adequate triac to use...

This AN from PHILIPS http://www.nxp.com/acrobat_download/applicationnotes/AN10384_1.pdf might be very explicit for electronicians; for me, it is too complicated.

Thanks for any info

Acetronics2
- 3rd November 2008, 10:47
Hi, Roger

your Triac has a "saturation voltage" ... Current ( RMS ! ) flows through ...

... P = ?? * ??

Roger ... you got excuses, cause, for once you've tried to calculate before burning your components ... lol

Amitiés from France

Alain

flotulopex
- 3rd November 2008, 11:08
Hello Alain,

You're right, I don't have enough triacs in stock to allow many tests ;)

Okay for the Irms but still knowing this, how must I understand the datasheet (this one, for example https://www.distrelec.com/distrelec/datasheets.nsf/WebAttachments/F016CC5163B42BFDC12572A30026F011/$File/BTA08-BTB08-T8_Data-E.pdf)?

Witch caracteristic is the Saturation Voltage then?

I don't know witch value(s) I need to take care of to calculate the triac... sorry, I'm only a an electrician...

flotulopex
- 6th November 2008, 13:31
I found what I was looking for here http://www.signindustry.com/electric/articles/2000-11_ALDORtriacexplainted.php3

amgen
- 18th November 2008, 01:29
i think most all triacs will produce about 1 watt per amp...
amgen