CF Lightbulb Dimmer
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From: Bret Cahill on 25 Mar 2010 11:53 > >>> Just start subtracting cycles. Below 25% - 40% power it'll start to > >>> flicker. > > >>> Bret Cahill > > >> Subtracting cycles? > > >> John > > > MOC3041 + triac + variable duty cycle pulse train perhaps? > > Don't think so. Using phase control the tube will not ignite below a certain > voltage. As that limit is not sharply defined and there will always be some > noise on the mains the tube starts to flicker. If you have to restart more often than the start up time it may not be easy. A night light works for just waking around but if you are looking for some small item and don't want to be permanently awakened by bright light you need a dimmer. See how long it takes me to find something that might not be cost effective in the USPTO. Bret Cahill
From: John Larkin on 25 Mar 2010 12:15 On Thu, 25 Mar 2010 08:43:39 -0700 (PDT), Bret Cahill <BretCahill(a)peoplepc.com> wrote: >> >Just start subtracting cycles. �Below 25% - 40% power it'll start to >> >flicker. >> >> >Bret Cahill >> >> Subtracting cycles? > >Instead of flashing 60 or 120 Hz it only flashes 30 or 60 cycles/sec. > >Eventually everyone will go to LED which is easy to operate at half >power: add a half bridge rectifier. Which converts 100/120 Hz flicker to 50/60. > >Lighting still requires a significant amount of power but it will be >pain free reducing this cost. > > >Bret Cahill > > > > Cycle-skipping controllers aren't used for lighting for obvious reasons. They are used for heaters and such. AC lighting dimmers are usually triac phase control, and most CFs don't like that. Some do. There are high-frequency electronic dimmers that sort of simulate a variac. Most CFs don't like them either. When a dimming function is integrated into the lamp or fixture, all sorts of electronic tricks become possible. John
From: David Eather on 25 Mar 2010 18:35 On 25/03/2010 10:46 PM, petrus bitbyter wrote: > "David Eather"<eather(a)tpg.com.au> schreef in bericht > news:wo-dnV1AQs8-3jbWnZ2dnUVZ_tyrnZ2d(a)supernews.com... >> On 25/03/2010 10:16 AM, John Larkin wrote: >>> On Wed, 24 Mar 2010 17:06:18 -0700 (PDT), Bret Cahill >>> <BretCahill(a)peoplepc.com> wrote: >>> >>>> Just start subtracting cycles. Below 25% - 40% power it'll start to >>>> flicker. >>>> >>>> >>>> Bret Cahill >>>> >>> >>> Subtracting cycles? >>> >>> John >>> >> MOC3041 + triac + variable duty cycle pulse train perhaps? > > > Don't think so. Using phase control the tube will not ignite below a certain > voltage. As that limit is not sharply defined and there will always be some > noise on the mains the tube starts to flicker. > > petrus bitbyter > > No, not phase control. The MOC3041 is a zero crossing triac opto coupler. This would work as the OP suggested - by subtracting mains cycles e.g. 4 cycles on 1 cycle off or 3 cycles on 2 cycles off. Would it work to dim a CF bulb. I don't know, but I don't think so.
From: David Eather on 25 Mar 2010 18:41 On 26/03/2010 2:15 AM, John Larkin wrote: > On Thu, 25 Mar 2010 08:43:39 -0700 (PDT), Bret Cahill > <BretCahill(a)peoplepc.com> wrote: > >>>> Just start subtracting cycles. Below 25% - 40% power it'll start to >>>> flicker. >>> >>>> Bret Cahill >>> >>> Subtracting cycles? >> >> Instead of flashing 60 or 120 Hz it only flashes 30 or 60 cycles/sec. >> >> Eventually everyone will go to LED which is easy to operate at half >> power: add a half bridge rectifier. > > Which converts 100/120 Hz flicker to 50/60. > >> >> Lighting still requires a significant amount of power but it will be >> pain free reducing this cost. >> >> >> Bret Cahill >> >> >> >> > > Cycle-skipping controllers aren't used for lighting for obvious > reasons. They are used for heaters and such. I didn't know such things existed. I designed one the other day (sort of) out of discretes so I could better control a space heater and decided I must have been mad to do something so useless. http://www.filedropper.com/missingcycles AC lighting dimmers are > usually triac phase control, and most CFs don't like that. Some do. > > There are high-frequency electronic dimmers that sort of simulate a > variac. Most CFs don't like them either. > > When a dimming function is integrated into the lamp or fixture, all > sorts of electronic tricks become possible. > > John > >
From: petrus bitbyter on 25 Mar 2010 19:05
"David Eather" <eather(a)tpg.com.au> schreef in bericht news:B_CdnZCuHfDdeDbWnZ2dnUVZ_tOdnZ2d(a)supernews.com... > On 25/03/2010 10:46 PM, petrus bitbyter wrote: >> "David Eather"<eather(a)tpg.com.au> schreef in bericht >> news:wo-dnV1AQs8-3jbWnZ2dnUVZ_tyrnZ2d(a)supernews.com... >>> On 25/03/2010 10:16 AM, John Larkin wrote: >>>> On Wed, 24 Mar 2010 17:06:18 -0700 (PDT), Bret Cahill >>>> <BretCahill(a)peoplepc.com> wrote: >>>> >>>>> Just start subtracting cycles. Below 25% - 40% power it'll start to >>>>> flicker. >>>>> >>>>> >>>>> Bret Cahill >>>>> >>>> >>>> Subtracting cycles? >>>> >>>> John >>>> >>> MOC3041 + triac + variable duty cycle pulse train perhaps? >> >> >> Don't think so. Using phase control the tube will not ignite below a >> certain >> voltage. As that limit is not sharply defined and there will always be >> some >> noise on the mains the tube starts to flicker. >> >> petrus bitbyter >> >> > > No, not phase control. The MOC3041 is a zero crossing triac opto coupler. > This would work as the OP suggested - by subtracting mains cycles e.g. 4 > cycles on 1 cycle off or 3 cycles on 2 cycles off. > > Would it work to dim a CF bulb. I don't know, but I don't think so. Ever build a heat controller like that. Even an incandescent bulb started to flicker below 60-70%. This method is definitively not the way to dim lights. A CLF may do slightly better as there is a rectifier and a bufferelco build in. Nevertheless I cannot imagine the flicker starts only at 40% when subtracting cycles. For a phase controlled triac it is much more likely. petrus bitbyter |