need help understanding thyristors - triac problem

Discussion in 'Homework Help' started by justtrying, Nov 11, 2011.

  1. justtrying

    Thread Starter Active Member

    Mar 9, 2011
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    352
    I am completely lost with thyristors...


    This is a problem from one of the worksheets on the site. I do not know how to do this. I tried to calculate the RC constant and converting it to angle, but I get:

    RC=165k*0.068uF = 11.2 ms which is 242 deg


    and I am pretty sure the approach is wrong anyway. I do not really now what to do. I know the diac conducts when breakdown voltage is reached and the triac is controlled from the gate. But the values are not specified and even if they were, I would still not now what to do.

    Does anyone know any site that actually goes through solving some of these instead of simply describing principles of operation? Especially controlling phases?
    [​IMG]
     
  2. justtrying

    Thread Starter Active Member

    Mar 9, 2011
    329
    352
    i got it! it was simpler than i thought - just write an expression for Vc.

    Question is still out on my SCR post (the one with no replies)
     
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