Re: Making an X-10 lamp module immune to dimming

[isw <isw@xxxxxxxxxxx>]

In article <1348346@xxxxxxxxxxxxxxxxxxx>,
 ddl@danlan.*com (Dan Lanciani) wrote:

> In article <isw-3AB4BB.10494406062008@xxxxxxxxxxxxxxxxxxxxxx>,
> isw@xxxxxxxxxxx (isw) writes:
> | In article <hpqdncmhFKn1b9XVnZ2dnUVZ_gWdnZ2d@xxxxxxx>,
> |  "Robert Green" <ROBERT_GREEN1963@xxxxxxxxx> wrote:
>
> | > As I understand it now, the pulse to the triac has to occur twice every
> | > cycle and has to be alternatingly negative and positive to allow each
> | > half
> | > of the AC cycle to pass.
> |
> | The pulses do not have to alternate in polarity; that's one of the neat
> | things about triacs.
>
> Though it is possible that you might want them to alternate to stay in
> the optimal triggering quadrants.

The triggering sensitivity is different, but the triac can always be
triggered.

> | > It sounds like the mod that uses the alternistor and the optoisolator
> | > does
> | > just that.  It seems that the optoisolator extracts the ZC data and then
> | > the
> | > additional circuitry creates its own full width pulse independent of
> | > whatever length pulse comes out of the IC.
> |
> | It sounds like you're attributing too much functionality to the
> | optoisolator; it doesn't *extract* anything. It's just a transistor that
> | turns on when light shines on it. And the light is the LED that's inside
> | it. The output of the opto just repeats whatever is on its input while
> | isolating the possibly dangerous voltage levels on the input side.
>
> The MOC3042 used in the modification is more than a simple optoisolator;

Yes, it is. I was not aware that was the device being used. Since the
output of the X-10 unit's IC is already phase synchronized, it's not
clear why something like that is necessary though.

Isaac