A friend with a small retail store. He has two lighted signs with
changeable letters on them. One sign has a flasher on it. The other one
is steady ON. The flashing one has incandescent bulbs, the steady one
has CFL bulbs. He wanted the "steady ON" one to flash, so he put a
flasher on the plug. In a few days the CFL bulbs were dead.
I looked at it and told him he cant use a flasher on CFL bulbs. It burns
them out quickly. Rather than buying incandescent bulbs for it, I was
wondering if LED bulbs can handle a flasher? Does anyone know?
Holiday lights are typically a bunch of LED's in series to operate off
the line voltage.
Standard home LED lights have a converter/regulator that drives the LED's.
It's likely that the LED's are fine, but the electronics are failing
because of the surge current.
On Monday, May 14, 2018 at 5:02:02 PM UTC-4, mike wrote:
Agree, it's probably that they don't like being turned on and off.
It may also depend on the cycle rate, ie that they don't like being
turned off then quickly back on. I would not be surprised if a
different brand, maybe ones from a name brand company, might be OK
with it, if they have a more tolerant power supply design.
He could do some experimenting.
That's why I asked. I know the holiday lights flash, but the flasher is
built right into them. Having a plug in flasher will surge the power
feeding these standard home LED bulbs.
You got that right. I had several of them CFL bulbs literally go up in
smoke and sparks. I actually went back to incendescent bulbs for a short
time, because of fear of having a fire from them CFLs. Now I have LED
lights in my whole house and out buildings. I still have about 20 brand
new CFL bulbs. I will probably give them to Goodwill or something. I'll
never use them.
The flashes are the same length. Without the bridge rectifier, every
other flash is dark (LEDs don't emit light when reverse biased).
Most (non-bridge-rectifier) strings I've seen have 2 series (each 25-35
LEDs) using opposite polarity, so there are still 120 flashes per second
(alternating between series).
Some of the flashes I add are about .5 second on. The others are 3 times
that long. You can see a video at http://notstupid.us/video/xmas2017.mp4
or http://notstupid.us/video/xmas2017.webm . Almost all of these lights
are LED. Flashing is done using a small computer (Arduino with
I didn't SEE it. That doesn't mean I don't know it's happening.
BTW, I have heard it. Once I replaced the microphone of an audio
recorder with a solar cell, and got to listen to the frequency of light.
It sounded about right for 120Hz.
There are a bunch of issues here.
A regular led that emits light at the color you see, when operated
off rectified AC, will have an intensity waveform that looks similar to
a 120 Hz. sinewave. The string of xmas tree lights may do that.
The white lights you buy for home use have a phosphor.
Some have a short-persistence phosphor and you can see the effects of
the flicker. Look at an AC powered fan and you may be able to see
the beat frequency in the pattern.
Some have a long-persistence phosphor that tends to smooth out the flicker.
Turn on your LED and let it warm up.
Turn it off.
If the light goes off instantly, you'll probably experience
If the light fades over a few seconds, you probably have a
long-persistence phosphor and will not see as many flicker artifacts.
You could do the same thing with a capacitor, but one big enough to
do much good wouldn't fit inside the bulb and would raise cost
On 5/14/2018 3:08 PM, snipped-for-privacy@Weiser.com wrote:
I've noticed CFL's in places like the bathroom where on and off for
short periods burn out faster. I assume it is thermal shock to other
components. CFL's and LED's also may have components that do not
outlast the bulb and those used may need more robust parts.
CFLs do have a shortened life when they are continuously turned off and
on. A programmable ballast will eliminate that but that's more for
linear type lamps. The medium base screw in lamps don't have that type
of ballast inside, thus, they will not last long with constant on and off.
Put them in areas where they will remain on for longer periods and use
LEDs for the areas with on/off action, or, simply use LEDs everywhere.
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