Chuck,
As you describe it there is no transformer in the circuit, so it should
be safe, but no guarantees ;-)
Tim Hughes
--- On Tue, 12/16/08, Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx> wrote:
> From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
> Subject: Re: [OM] [OT] LED Christmas lights and an incandescent dimmer???
> To: "Olympus Camera Discussion" <olympus@xxxxxxxxxxxxxxxxx>
> Date: Tuesday, December 16, 2008, 12:26 PM
> Thanks, Tim. Any chance I can fry the lights?
>
> Chuck Norcutt
>
> Tim Hughes wrote:
> > I would guess the Leds have a Cheap 1N4004 diode
> connected in series
> > with them, so they aren't damaged by the possible
> large reverse
> > voltage, or they may be connected in pairs back to
> back so one LED
> > conducts on one half of cycle and the other on the
> other half cycle.
> > They must also include a current limit of some sort,
> probably just a
> > small resistor potted into the connector. In theory
> a triac dimmer
> > should work over part of its range if the string uses
> with a current
> > limit resistor, but it may be the current draw
> (probably ~20mA) is so
> > low the dimmer circuit itself will not function
> properly.
> >
> > If it were me I would just try it.
> >
> > You could also try connecting a small incandescent
> light in parallel
> > with the light string, to increase the load a bit for
> the dimmer to
> > operate on.
> >
> > tim Hughes
> >
> >
> > --- On Mon, 12/15/08, Chuck Norcutt
> <chucknorcutt@xxxxxxxxxxxxxxxx>
> > wrote:
> >
> >> From: Chuck Norcutt
> <chucknorcutt@xxxxxxxxxxxxxxxx> Subject: Re:
> >> [OM] [OT] LED Christmas lights and an incandescent
> dimmer??? To:
> >> "Olympus Camera Discussion"
> <olympus@xxxxxxxxxxxxxxxxx> Date:
> >> Monday, December 15, 2008, 7:54 PM Thanks, but I
> think I'll just go
> >> buy an inline switch. :-)
> >>
> >> Chuck Norcutt
> >>
> >> WayneS wrote:
> >>> Then I don't see why a dimmer should not
> work. The
> >> string probably
> >>> has enough in series to drop 120VAC, and the
> natural
> >> diode
> >>> action means they only use 1/2 of the cycle.
> the
> >> diodes must have
> >>> good reverse voltage breakdown. Peak voltage
> is 163V.
> >> divide by two and
> >>> you get 80 bulbs in series.
> >>>
> >>> The dimmer effect may be a bit non-linear, but
> should
> >> work.
> >>> Wayne.
> >>>
> >>> At 07:24 PM 12/15/2008, you wrote:
> >>>> These LEDs connect directly to the 120v
> supply.
> >> There is no visible
> >>>> converter. The plugs are even normal size
> for an
> >> incandescent string of
> >>>> lights so I don't think there's
> anything
> >> hiding in there except a fuse.
> >>>> They look exactly like a normal string of
> small
> >> incandescent bulbs
> >>>> except that they're LEDs. The bulbs
> also pop
> >> in and out of sockets like
> >>>> they would if they were small incandescent
> bulbs.
> >> Bulbs are stated to
> >>>> be 2 volts and 0.04 watts. A box of them
> consists
> >> of either 2 strings
> >>>> of 90 bulbs or 3 strings of 60 bulbs for
> 180 bulbs
> >> drawing only 7.2 watts.
> >>>> Chuck Norcutt
> >>>>
> >>>> WayneS wrote:
> >>>>> LEDs are DC so there must be an AC to
> DC
> >> converter. Without knowing
> >>>>> the details of that converter it may,
> or may
> >> not work.
> >>>>> Wayne
> >>>>>
> >>>>> At 04:56 PM 12/15/2008, Chuck wrote:
> >>>>>> What happens if I plug my LED
> Christmas
> >> tree lights (120v) into an
> >>>>>> incandescent dimmer switch? ...
> >>>
> >>>
> >>
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