Home LED Flickers

On Wednesday, 12 December 2018 19:09:19 UTC, pf...@aol.com wrote:

On Wednesday, December 12, 2018 at 2:00:49 PM UTC-5, tabby wrote:
On Wednesday, 12 December 2018 17:47:10 UTC, pf...@aol.com wrote:
Thought not.

Peter Wieck
Melrose Park, PA

you've earnt your ignorance and you get to keep it.

For someone who rears up like an injured virgin when called out, you have lost a priceless opportunity to humiliate your oppressor.

That would be earned. Whereas Earnt is correct, it is non-standard and somewhat pretentious. Similar to your inferred virginity.

Peter Wieck
Melrose Park, PA

It seems I overestimated you.

 

[mike]

On 12/12/2018 8:00 AM, pfjw@aol.com wrote:

As an LED is a go/no-go device, flicker is indicative of a condition outside the emitter. Full stop.

Peter Wieck
Melrose Park, PA

I love it when people say "full stop" like that makes 'em right.
So, you've never seen a thermal intermittent...

Unlikely, maybe. Full Stop, not so much.

 

[pfjw@aol.com]

On Wednesday, December 12, 2018 at 3:07:34 PM UTC-5, mike wrote:

On 12/12/2018 8:00 AM, pfjw@aol.com wrote:
As an LED is a go/no-go device, flicker is indicative of a condition outside the emitter. Full stop.

Peter Wieck
Melrose Park, PA

I love it when people say "full stop" like that makes 'em right.
So, you've never seen a thermal intermittent...

Unlikely, maybe. Full Stop, not so much.

A thermal intermittent would not apply to the emitter. It would very much apply to the driver, socket, contacts, whatever. I have seen my fair share, naturally - and none of them were an emitter fault.

Peter Wieck
Melrose Park, PA

 

[Fox's Mercantile]

On 12/12/18 11:26 AM, pfjw@aol.com wrote:

Another challenging variable for LED lamps to avoid flickering
is through dimming.

Surprisingly, the two cheap 60 Watt dimmable LEDs I bought at Walmart,
work just fine with the old photo cell socket "night light" adapters.
Designed to work with incandescent bulbs, I found out they only take
month or two to kill halogen bulbs.

--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[whit3rd]

On Wednesday, December 12, 2018 at 9:26:36 AM UTC-8, pf...@aol.com wrote:

On Wednesday, December 12, 2018 at 12:16:11 PM UTC-5, tabb...@gmail.com wrote:

I know you think you're right about everything, but you're not. LEDs do sometimes go into flickering mode.

Now, show us a link where the emitter is the cause of the flicker, and not the driver.

 

[whit3rd]

On Wednesday, December 12, 2018 at 9:26:36 AM UTC-8, pf...@aol.com wrote:

On Wednesday, December 12, 2018 at 12:16:11 PM UTC-5, tabb...@gmail.com wrote:

I know you think you're right about everything, but you're not. LEDs do sometimes go into flickering mode.

Now, show us a link where the emitter is the cause of the flicker, and not the driver.

Oh, it happens; I've had multi-LED panels where handling the PC board (not the power
brick) caused/stopped the flicker. Not solder, either, some kind of internal-to-the-LED
package or thermal fault. Replaced four or five elements, and the lamp works fine now
(though my replacement LEDs were a mismatch for the original 'warm' white).

 

[Dave Platt]

I know you think you're right about everything, but you're not. LEDs do sometimes go into flickering mode.

Now, show us a link where the emitter is the cause of the flicker, and not the driver.

Oh, it happens; I've had multi-LED panels where handling the PC board (not the power
brick) caused/stopped the flicker. Not solder, either, some kind of internal-to-the-LED
package or thermal fault. Replaced four or five elements, and the lamp works fine now
(though my replacement LEDs were a mismatch for the original 'warm' white).

A lot of the cheap Chinese-made LED bulbs for automotive use seem to
develop flicker problems. One or more series strings of LEDs start
flashing on and off, somewhat randomly, while other strings are
unaffected. These don't have a "driver" per se, just a series
resistor and (in some cases) a bypass cap.

I haven't been able to tell whether the failure is in one of the
individual LEDs in the string, or in the solder bonding of the LED to
the substrate. I sorta suspect the latter... bad RoHS-safe-solder
junctions, perhaps. The flickering seems to be at least partially a
thermal cycling problem... LED comes on, chip heats up, bad junction
opens, LED cools down, lather/rinse/repeat.

The time constant is typically a fraction of a second... more of a
blink than a flicker.

 

[John-Del]

On Wednesday, December 12, 2018 at 3:44:41 PM UTC-5, pf...@aol.com wrote:

On Wednesday, December 12, 2018 at 3:07:34 PM UTC-5, mike wrote:
On 12/12/2018 8:00 AM, pfjw@aol.com wrote:
As an LED is a go/no-go device, flicker is indicative of a condition outside the emitter. Full stop.

Peter Wieck
Melrose Park, PA

I love it when people say "full stop" like that makes 'em right.
So, you've never seen a thermal intermittent...

Unlikely, maybe. Full Stop, not so much.

A thermal intermittent would not apply to the emitter. It would very much apply to the driver, socket, contacts, whatever. I have seen my fair share, naturally - and none of them were an emitter fault.

Peter Wieck
Melrose Park, PA

I've seen plenty of intermittent or even slow to start LED emitter chips. In LCD backlights, I've changed over two thousand of them in the last 5 years.

But, the majority of those were either shorted or open, but the intermittent ones busted my ass enough to force a change of procedure in bench testing before the display was reassembled. Several thermal cycles as well as under-volting and over-volting the array will ferret out most intermittents.

 

[John-Del]

On Wednesday, December 12, 2018 at 8:11:10 PM UTC-5, John-Del wrote:

On Wednesday, December 12, 2018 at 3:44:41 PM UTC-5, pf...@aol.com wrote:
On Wednesday, December 12, 2018 at 3:07:34 PM UTC-5, mike wrote:
On 12/12/2018 8:00 AM, pfjw@aol.com wrote:
As an LED is a go/no-go device, flicker is indicative of a condition outside the emitter. Full stop.

Peter Wieck
Melrose Park, PA

I love it when people say "full stop" like that makes 'em right.
So, you've never seen a thermal intermittent...

Unlikely, maybe. Full Stop, not so much.

A thermal intermittent would not apply to the emitter. It would very much apply to the driver, socket, contacts, whatever. I have seen my fair share, naturally - and none of them were an emitter fault.

Peter Wieck
Melrose Park, PA



I've seen plenty of intermittent or even slow to start LED emitter chips. In LCD backlights, I've changed over two thousand of them in the last 5 years.

But, the majority of those were either shorted or open, but the intermittent ones busted my ass enough to force a change of procedure in bench testing before the display was reassembled. Several thermal cycles as well as under-volting and over-volting the array will ferret out most intermittents.

I forgot to add that in no case have I seen an LED chip "flicker", at least not in a steady cadence. OP never clarified what exact kind of flicker he had but I think we've gotten off the subject a bit.

 

In article <5448bce3-35a9-480c-b527-069ff31fc16b@googlegroups.com>,
pfjw@aol.com <peterwieck33@gmail.com> wrote:
>Now, show us a link where the emitter is the cause of the flicker, and not the driver.

A Practical Example of GaN-LED Failure Cause Analysis by Application of Combined Electron
Microscopy Techniques

Page 2: ...after a short time, the blue and white LEDs either started to flicker, showed a
reduced light output, or spontaneously failed completely, whereas the red LEDs present in
the same module in parallel continued to function correctly.

Page 4: The further observation of cross-sections of the nitride layers inside revealed the
reasons for the devices’ malfunctions. In Figure 4, an example of a cross-section of an
LED exhibiting failure type (B) (flickering dark and bright) is shown. One can see that
beside the bond foot, the nitride semiconductor layer has slightly lost contact to the back
side of the device and, moreover, shows tiny cracks across the layer.

http://www.mdpi.com/1996-1944/10/10/1202/pdf

Sceptre
--
sceptre@sdf.org
SDF Public Access UNIX System - http://sdf.org

 

[Fox's Mercantile]

On 12/13/18 2:58 AM, tubeguy@myshop.com wrote:

I bought a bunch of them at Walmart and then Dollar
Tree was selling some for ONE DOLLAR (US) for TWO PACK. I stocked up.
I am not sure which is in this fixture, but no others flicker from
either store.....

So, why don't ya just replace the thing and be done with it?

--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

On Tue, 11 Dec 2018 18:23:45 -0800, mike <ham789@netzero.net> wrote:

On 12/11/2018 4:44 PM, tubeguy@myshop.com wrote:
I got a 60W Equliv. LED bulb in a fixture that flickers all the time.
Its not very old. It does produce enough light but gets annoying after
awhile. They only cost a buck or two, so i'll just replace it, but I
wonder what is causing the flicker?

Does the fixture wire it directly to the mains or does it have some kind
of switching, wireless, touch, dimmer, anything but direct wire to the
mains?

What's your definition of flicker?
Some bulbs have noticeable flicker at line frequency.
Most flicker at a much lower rate if you put some
electronics in the middle. It's the electronics that
expects the resistive load of an incandescent that flickers.

My guess is a cheap electrolytic in the rectifier, but I have never
really seen a schematic for how they are wired.

I have it in my hallway. Standard switch only, no dimmer. Fixture is a
common "BOOB LIGHT". (Google that). I haave 3 such fixtures in the
house, all have LEDs. Only this one in the hallway flickers. Neither the
incan bulb or CFL that used to be in that fixture flickered. So its
likely the LED bulb. I bought a bunch of them at Walmart and then Dollar
Tree was selling some for ONE DOLLAR (US) for TWO PACK. I stocked up.
I am not sure which is in this fixture, but no others flicker from
either store.....

 

[PeterSchneider]

Am 12.12.2018 um 01:44 schrieb tubeguy@myshop.com:

I got a 60W Equliv. LED bulb in a fixture that flickers all the time.
Its not very old. It does produce enough light but gets annoying after
awhile. They only cost a buck or two, so i'll just replace it, but I
wonder what is causing the flicker?

My guess is a cheap electrolytic in the rectifier, but I have never
really seen a schematic for how they are wired.

If the bulb has an capacitive power supply could be a defective
rectifier leeds to flickering.

 

[Ralph Mowery]

In article <sd-dnZMcZ4z1uI_BnZ2dnUU7-NnNnZ2d@giganews.com>,
jdangus@att.net says...

On 12/13/18 2:58 AM, tubeguy@myshop.com wrote:
I bought a bunch of them at Walmart and then Dollar
Tree was selling some for ONE DOLLAR (US) for TWO PACK. I stocked up.
I am not sure which is in this fixture, but no others flicker from
either store.....

So, why don't ya just replace the thing and be done with it?

My thoughts too. I have a celaing fan with 4 bulbs in it. I put LEDs
in it a while back replacing the CFLs. I seldom use the fan part, bu
the lights stay on from about 9 in the morning to 12 at night almost
every day. A few days ago one of the LEDs would go off for about 2
seconds and come on for a short time and off again. I just replaced it.
I may open it up just to see one day, but have not taken time to even
worry about it. It may have been of the free ones the power company was
giving out a few years ago. At one time they gave out about a dozen CFL
and then a dozen LEDs a few years later.

One and two dollar or less items are just not worth the time to worry
about when they last over 6 months.

 

[Bennett Price]

On 12/12/2018 5:13 PM, John-Del wrote:

On Wednesday, December 12, 2018 at 8:11:10 PM UTC-5, John-Del wrote:
On Wednesday, December 12, 2018 at 3:44:41 PM UTC-5, pf...@aol.com wrote:
On Wednesday, December 12, 2018 at 3:07:34 PM UTC-5, mike wrote:
On 12/12/2018 8:00 AM, pfjw@aol.com wrote:
As an LED is a go/no-go device, flicker is indicative of a condition outside the emitter. Full stop.

Peter Wieck
Melrose Park, PA

I love it when people say "full stop" like that makes 'em right.
So, you've never seen a thermal intermittent...

Unlikely, maybe. Full Stop, not so much.

A thermal intermittent would not apply to the emitter. It would very much apply to the driver, socket, contacts, whatever. I have seen my fair share, naturally - and none of them were an emitter fault.

Peter Wieck
Melrose Park, PA



I've seen plenty of intermittent or even slow to start LED emitter chips. In LCD backlights, I've changed over two thousand of them in the last 5 years.

But, the majority of those were either shorted or open, but the intermittent ones busted my ass enough to force a change of procedure in bench testing before the display was reassembled. Several thermal cycles as well as under-volting and over-volting the array will ferret out most intermittents.

I forgot to add that in no case have I seen an LED chip "flicker", at least not in a steady cadence. OP never clarified what exact kind of flicker he had but I think we've gotten off the subject a bit.

I've had bad luck, irregular flicking - with one brand of LED
'40w''candelabra' bulbs in which the 'filaments' were plainly visible
In the bulb - glass envelope - some filaments flickered while others
were fine. Occurred in 4 different bulbs. As I recall each bulb had
4 strings (filaments) of LEDs. Sorry, I don't remember the brand.

 

[Chuck]

On Thu, 13 Dec 2018 15:33:54 -0800, Bennett Price
<NOTbjprice@cal.berkeley.edu> wrote:

On 12/12/2018 5:13 PM, John-Del wrote:
On Wednesday, December 12, 2018 at 8:11:10 PM UTC-5, John-Del wrote:
On Wednesday, December 12, 2018 at 3:44:41 PM UTC-5, pf...@aol.com wrote:
On Wednesday, December 12, 2018 at 3:07:34 PM UTC-5, mike wrote:
On 12/12/2018 8:00 AM, pfjw@aol.com wrote:
As an LED is a go/no-go device, flicker is indicative of a condition outside the emitter. Full stop.

Peter Wieck
Melrose Park, PA

I love it when people say "full stop" like that makes 'em right.
So, you've never seen a thermal intermittent...

Unlikely, maybe. Full Stop, not so much.

A thermal intermittent would not apply to the emitter. It would very much apply to the driver, socket, contacts, whatever. I have seen my fair share, naturally - and none of them were an emitter fault.

Peter Wieck
Melrose Park, PA



I've seen plenty of intermittent or even slow to start LED emitter chips. In LCD backlights, I've changed over two thousand of them in the last 5 years.

But, the majority of those were either shorted or open, but the intermittent ones busted my ass enough to force a change of procedure in bench testing before the display was reassembled. Several thermal cycles as well as under-volting and over-volting the array will ferret out most intermittents.

I forgot to add that in no case have I seen an LED chip "flicker", at least not in a steady cadence. OP never clarified what exact kind of flicker he had but I think we've gotten off the subject a bit.

I've had bad luck, irregular flicking - with one brand of LED
'40w''candelabra' bulbs in which the 'filaments' were plainly visible
In the bulb - glass envelope - some filaments flickered while others
were fine. Occurred in 4 different bulbs. As I recall each bulb had
4 strings (filaments) of LEDs. Sorry, I don't remember the brand.

Same here. Out of 6 Sylvania candelabra bulbs, 3 did the exact same
thing. Replaced with a different brand and no flickering.

 

On Tuesday, December 11, 2018 at 7:44:07 PM UTC-5, tub...@myshop.com wrote:

I got a 60W Equliv. LED bulb in a fixture that flickers all the time.
Its not very old. It does produce enough light but gets annoying after
awhile. They only cost a buck or two, so i'll just replace it, but I
wonder what is causing the flicker?

My guess is a cheap electrolytic in the rectifier, but I have never
really seen a schematic for how they are wired.

This is my opinion. They are made very cheaply they aren't made with much shielding so anything can cause them to flicker. Now be careful because cans have protection from overheating and it's possible the LED module is not compatible with the model of can fixture you have so that's another possibility. I would try another unit see how things go.

 

On Sunday, 16 December 2018 20:46:34 UTC, frankco...@gmail.com wrote:

On Tuesday, December 11, 2018 at 7:44:07 PM UTC-5, tub...@myshop.com wrote:

I got a 60W Equliv. LED bulb in a fixture that flickers all the time.
Its not very old. It does produce enough light but gets annoying after
awhile. They only cost a buck or two, so i'll just replace it, but I
wonder what is causing the flicker?

My guess is a cheap electrolytic in the rectifier, but I have never
really seen a schematic for how they are wired.

This is my opinion. They are made very cheaply they aren't made with much shielding so anything can cause them to flicker.

that simply isn't so. The nature of the circuits makes them robust against RFI.


NT

 

[Tim R]

On Wednesday, December 12, 2018 at 8:26:18 AM UTC-5, pf...@aol.com wrote:

There are two parts of an LED lamp/fixture.

a) The LED emitters themselves: These are pretty generic beasts, and while not-quite-one-size-fits-all, the same emitter may provide light from between 3000K to 5000K. They are also pretty bullet-proof.

b) The "Driver" - which is a device that takes current from some source and makes it into what the emitters want for a particular type (Temperature and CRI) of output.

Massive RF output - 5% - so massive as to even step on cell phones and blue-tooth frequencies on rare occasions, but mostly lower bands.

Hmm. Our Christmas tree has a couple hundred LED lights on it. Am I broadcasting RF to the neighborhood?

 

[pfjw@aol.com]

On Monday, December 17, 2018 at 11:11:28 AM UTC-5, Tim R wrote:

On Wednesday, December 12, 2018 at 8:26:18 AM UTC-5, pf...@aol.com wrote:
There are two parts of an LED lamp/fixture.

a) The LED emitters themselves: These are pretty generic beasts, and while not-quite-one-size-fits-all, the same emitter may provide light from between 3000K to 5000K. They are also pretty bullet-proof.

b) The "Driver" - which is a device that takes current from some source and makes it into what the emitters want for a particular type (Temperature and CRI) of output.

Massive RF output - 5% - so massive as to even step on cell phones and blue-tooth frequencies on rare occasions, but mostly lower bands.

Hmm. Our Christmas tree has a couple hundred LED lights on it. Am I broadcasting RF to the neighborhood?

Depends on the driver. You would know if you were.

Peter Wieck
Melrose Park, PA