Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
01/16/07 13:35
Read: times


 		 #130876 - Zero Crossing detector woes
I'm developing a ckt. to phase control a triac by using the INT1 as a zero crossing sensor. The correspomdimg ISR is supposed to cause different delays for firing a triac circuit.

The secondary of the transformer is connected to a bridge (DB017) which is in turn connted to pins 1 and 2 of the optocouple 4N35. I get a clean pulsating wave-form at the output of the 4N35 (emmitter, pin4 ). (w/o connecting to P3.3).

However the moment I connect this output to P3.3 ( INT1) the pulsating wave-form distorts (the ground actually shifts up by 5V). Needless to say I get no output at the delay output pin.

Why is connecting the P3.3 causing this ?
Any links to practical zero crossing detector circuits?

Thanks,
Rishi

List of 31 messages in thread
TopicAuthorDate
Zero Crossing detector woes            01/01/70 00:00      
   "Bible" time.            01/01/70 00:00      
      proper connecton 4n35?            01/01/70 00:00      
   Try MOC 3041 or MOC 3043            01/01/70 00:00      
   links            01/01/70 00:00      
   Why make simple matters worse?            01/01/70 00:00      
      I would never do this!            01/01/70 00:00      
         Sounds like a recipe for a Darwin Award.            01/01/70 00:00      
            Total agree!            01/01/70 00:00      
         i had did this with opampe !            01/01/70 00:00      
   Have tried out the suggestions!            01/01/70 00:00      
      It will get you 'excited' when you reverse the plu            01/01/70 00:00      
   Schematic Added - Am I asking for too much?            01/01/70 00:00      
      Been there; done that            01/01/70 00:00      
      Jerson is right            01/01/70 00:00      
      Post the code !here!            01/01/70 00:00      
   URL for schematic            01/01/70 00:00      
      You can avoid the bridge            01/01/70 00:00      
      You need a pull up            01/01/70 00:00      
      Will not work!            01/01/70 00:00      
         will work - 4511 has active "high" outputs            01/01/70 00:00      
            what is a 4511            01/01/70 00:00      
               It's a CD4511, of course            01/01/70 00:00      
                  of course?            01/01/70 00:00      
            No, it will not            01/01/70 00:00      
               agree            01/01/70 00:00      
         Mistake in writing            01/01/70 00:00      
   just remembered this one . Do not know if            01/01/70 00:00      
   Am making modifications            01/01/70 00:00      
      a few answers            01/01/70 00:00      
   It is a HEF4511B - sorry for the short form.            01/01/70 00:00      

Back to Subject List