Can LED bulbs be connected to a flasher?

[Bud]

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?

[Mark Lloyd]

They should. I've been flashing LED holiday lights since 2005. I do not see a higher failure rate than for those that stay on.

[mike]

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.

[trader_4]

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.

[Frank]

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.

[Meanie]

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.

[Clare Snyder]

Household LEDS are a LOT more durable than CFL bulbs CFL ballasts in general are JUNK

[Bud]

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.

[gregz]

Holiday lights flash 60 times a second, 120 if off a bridge rectifier.

Greg

[rbowman]

[Mark Lloyd]

[snip]

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

or . Almost all of these lights are LED. Flashing is done using a small computer (Arduino with solid-state relays).

[trader_4]

60 or 120 times a second seems like a very high rate. It's the refresh rate of displays. I'm surprised you'd even see it or that it would be the desirable kind of flashing for holiday lights.

[Mark Lloyd]

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.

[mike]

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 flicker artifacts.

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 significantly.

[Terry Coombs]

  Are you and Mike both reading comprehension impaired ? He clearly stated that it was CFL bulbs that have failed  .