In message <001f01c096cd$c6d3b840$b2bcb2d1@engine2000>, Andre Abelian
<engelec@EARTHLINK.NET> writes
>Hi to all engineers.
>
>I am making a simple light dimmer for my kids and
>I am having hard time to make it work with a triac.
>I am using pic16c72 hardware pwm , MOC3010, and Power triac.
>The pic works fine I checked it with scope when I connect it
>thru opto triac the lamp suppose to turn on low and go higher brightness
>all I see while PWM goes from 0-70 % blinks a few times
>and stays on on higher duty cycle for load I use regular 110 v lamp.
>when I connect any LED on PIC output I can see it slowly increases
>the brightness I am not sure if same thing happening inside of MOC3010.
>I do not know what is wrong with it any help will highly appreciated.
>attached is the schematic.

You can't fed a triac with a PWM output, you have to adjust the point on
each mains cycle that you trigger the triac. Basically you need to
detect the zero-crossing point of each mains half cycle, then delay
before triggering the triac - the shorter the delay the brighter the
lamp (being careful not to delay longer than one half cycle).
--

Nigel.

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