Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!wuarchive!udel!udccvax1!andrew
From: andrew@vax1.acs.udel.EDU (Andrew W Hamilton)
Newsgroups: sci.electronics
Subject: Triac blues...help!
Message-ID: <4968@udccvax1.acs.udel.EDU>
Date: 10 Nov 89 01:22:46 GMT
Reply-To: andrew@vax1.acs.udel.EDU (Andrew W Hamilton)
Organization: University of Delaware
Lines: 19

I'm trying to switch a standard 100W light bulb by using a 400V 6A triac
and a triac based optocoupler, but no matter what I do, the light will not shut 
off.  It even remains on with no power connected to the DC side of the circuit
because there seems to be only 63 ohms between the two main terminals of
the triac at all times, so current is always flowing.
Any Ideas?


         470ohm   _______     220ohm
   +  +--/\/\/---|1     6|----/\/\/------+------LIGHT---------+
  9V             |       |               |
   -  +----------|2     5|nc       +---Triac              120V AC
                 |       |         |     |
               nc|3_____4|---------+     +--------------------+
                optocoupler

Thanks in advance,

Andrew.