Just start subtracting cycles. Below 25% - 40% power it'll start to flicker.
Bret Cahill
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
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.
Lighting still requires a significant amount of power but it will be pain free reducing this cost.
Bret Cahill
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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
Which converts 100/120 Hz flicker to 50/60.
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
-- No. In the case of conventional fluorescent lamps operating from 60Hz mains, they flash 120 times per second because the positive-going as
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.
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.
AC lighting dimmers are
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
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
o
Or maybe the LED itself is a half bridge rectifier.
It probably gets irritating below 30.
Yea! That's the right term!
I saw some ads on Google.
Is anything at Home Depot?
Bret Cahill
Only if the AC supply voltage is low. LEDs don't like to be zenered.
John
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.
t to
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
I built a kiln controller using a zero-crossing triac optocoupler, and at low duty cycles you could see flicker in other incandescent lights in the house!
Best regards,
Bob Masta DAQARTA v5.10 Data AcQuisition And Real-Time Analysis
-- Half _wave_ rectifier
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