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

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"Jeff Volp" <JeffVolp@xxxxxxx> wrote in message
news:upJ1k.19034$102.546@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> "Robert Green" <ROBERT_GREEN1963@xxxxxxxxx> wrote in message
> news:hOWdnZPUEpdFotrVnZ2dnUVZ_jWdnZ2d@xxxxxxxxxx
>
> > I believe the first test will just be to simply disconnect pin 8 from
the
> > control line.  Hopefully it will be easy to rebridge if that turns out
not
> > to work.  Also, hopefully, it won't incinerate itself after snipping
that
> > line.  I guess I can trot out the old 20mm ammo box I have for
containment
> > of explosive experiments - well, maybe just leave it on a fireproof
> > surface
> > to test . . .
>
> Whoops, that was a typo before.  Pin 8 is used for the local control.
> Snipping that will only disable local control.  Pin 6 drives the triac.
> That line is essential.  If snipped there will be no on/off control at
all.
> The dimming phase control is inside the IC.

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 dimmer does its magic by narrowing the width
of that pulse - shorter means less power gets to the device and its dimmer.
As I said to Dan, I thought a triac was just a very fast solid state relay.

> It might be possible to extend the pulse coming out of the IC so that if
> there is ANY pulse at all, the transistor will remain on through the
> beginning of the next cycle so the unit will switch on right after the
zero
> crossing.

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.  So if the module was dimming the
output, it wouldn't matter because that pulse is driving a latching circuit
that stays on until the next ZC, correct?

--
Bobby G.