CF Lightbulb Dimmer
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From: John Larkin on 25 Mar 2010 21:07 On Fri, 26 Mar 2010 08:41:29 +1000, David Eather <eather(a)tpg.com.au> wrote: >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 > Zero-crossing triac controller chips have been around for a long time. They dole out integral bursts of AC line cycles. Heaters like restauarant deep-fat friers use these. EMI and magnetic-acoustic noise are low and there's no DC component to saturate distribution transformers. There is debate about the meaning of "power factor" into a resistive load driven by these gadgets. John
From: Bret Cahill on 25 Mar 2010 23:49 > >> >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. Or maybe the LED itself is a half bridge rectifier. > Which converts 100/120 Hz flicker to 50/60. It probably gets irritating below 30. > >Lighting still requires a significant amount of power but it will be > >pain free reducing this cost. > > >Bret Cahill > > Cycle-skipping Yea! That's the right term! > 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. I saw some ads on Google. Is anything at Home Depot? Bret Cahill
From: John Larkin on 25 Mar 2010 23:56 On Thu, 25 Mar 2010 20:49:56 -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. > >Or maybe the LED itself is a half bridge rectifier. Only if the AC supply voltage is low. LEDs don't like to be zenered. John
From: David Eather on 25 Mar 2010 23:56 On 26/03/2010 11:07 AM, John Larkin wrote: > On Fri, 26 Mar 2010 08:41:29 +1000, David Eather<eather(a)tpg.com.au> > wrote: > >> 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 >> > > > Zero-crossing triac controller chips have been around for a long time. > They dole out integral bursts of AC line cycles. Heaters like > restauarant deep-fat friers use these. EMI and magnetic-acoustic noise > are low and there's no DC component to saturate distribution > transformers. I knew about the controller chips. They existed before I went to "sleep" (one day I went to bed, 12 years later I woke up and half the semiconductor manufacturers I knew no longer existed and Motorola just made telephones!) I just didn't think people would use them that way - I thought a thermostat and EMI filter would be the go. > > There is debate about the meaning of "power factor" into a resistive > load driven by these gadgets. > > John > >
From: Bret Cahill on 26 Mar 2010 00:38
> >> >> >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. > > >Or maybe the LED itself is a half bridge rectifier. > > Only if the AC supply voltage is low. LEDs don't like to be zenered. You can take out the blue LED from a dollar store night light and wire up 4 - 6 whiteish LED Christmas lights and then hot melt glue the string to the wall. I'm guessing the power consumption is still about 1/4 watt -- not worth turning off. I have very little credibility in interior design. You'd have to get some personality like Martha Stewart to get it to sell. Bret Cahill |