LED Celling stay glow.Can I stop that?

[Stardian101]

Hello ..
We have a LED lamp
its in ceiling of the room which i sleep in it
the problem :
the lamp stay light after switch off
like this:

Is there method to modify it circuit to stop that
i want it to be like normal lamp

Electrical student,4th , thanks

 

[Chemelec]

Put Another Power Switch on it to Really Turn Off the Power.

 

[shrtrnd]

I don't know your electrical grid or the unit. My suggestion, if it's possible with whatever your electrical system is,
to reverse the polarity if this is an AC unit (Turn the plug around?), and see if your power grid neutral is the issue.
(I am completely unfamiliar with what you have there, don't try that if your electrical grid uses some kind of polarized plug input)
Most of the problems I've seen with these LED lamps is current leakage through the diode/semiconductor after you
turn the unit 'off'. Usually solved by appropriate placement of a small resistor.
But again, I don't know your input power grid, or the lamp itself.
Most of us here will ask you to give us a brand-name and model number if you can find it on your unit, to see
if we can find a schematic on how it's wired. You might provide that if you can.

 

[Audioguru]

It already is a normal lamp. Its electrical input has 3 wires like most lamps. The wires are ground, neutral and line.
Your switch is supposed to connect and disconnect the line wire but you probably have the switch or the lamp connected wrong.

 

[Stardian101]

Chemelec,
Where? I don't know ,thanks for reply

shrtrnd
I put pics in the link:
https://www.flickr.com/gp/149910830@N03/7ft529
Thanks so much

Audioguru
there is tow wires
i think, its for N & L as in image

I suggest that
i can modify the circuit only to make it as fluorescent lamp

 

[Audioguru]

The light switch is supposed to disconnect the L wire when the switch is turned off. If it doesn't then the switch should be replaced.

 

[Externet]

Seen that behavior several times, the leds faintly lit with power switch off, discernible only in a dark room. My bedside lamp does it, and is only wired to the outlet with a two-prong plug, no ground.

Has to be some leaky component conducting μA when switched off, and have not paid enough attention nor interest in solving. Guessing, the lubricant around switch contacts, or the transformer windings picking EM.

Have you tried a DPDT wall switch instead ? Or a 1MΩ resistor across the power terminals at the led lamp assembly ?

 

[Bluejets]

As Shrtrnd says, depends on your electrical installation however, most of the problem like this comes from a rising neutral voltage (above ground).

The fix with fluro lights was to reverse the line and neutral connections.

Whether or not it will work with the new LEDs and their power supply units is another question.

Alternative is to get a qualified electrician to check out your installation, maybe some of your earth bonding has failed or on the way out.
Other than that, just use a tungsten light or double insulated LED fitting.

 

[Audioguru]

The phosphor in my compact fluorescent light bulbs glow for about 1 minute after being switched off. Maybe the LEDs in this lamp have a new phosphor that glows for awhile?

 

[shrtrnd]

I'm still thinking this has to do with leakage current through the diodes (the LEDs are diodes).
I don't know the electronics skill level of Stardian101. Modifying a new unit is always questionable to me,
but I imagine having the LEDs dimly 'ON' continuously when you're trying to sleep is a pain.
I, would insert a 1K ohm resistor, maybe 1/2W across the LED input line and see what happens.
Then adjust the resistor if/as needed (checking to make sure the 1/2 resistor doesn't overheat during
the experimenting process).
I would think the resistor would keep the LEDs from glowing when the unit is turned 'OFF'.
I've seen this type of a problem when there are a lot of LEDs tied together like this.
Like I said, don't know Stardian101's electronics skill level, but that's what I would try.
But I'm an experimenter, and Stardian101 might not be.

 

[Bluejets]

Problem with the fluros was capacitive coupling between neutral and the earth frame.

 

[Audioguru]

Neutral and Earth are supposed to be connected together. The light switch is supposed to connect and disconnect the Line wire not the Neutral.

 

[shrtrnd]

I'm trying to figure-out how flourescents got involved here. (vs. Stardian101's original post)
My thinking is like yours Audioguru, but I've heard from a couple of guys (on this site) from some smaller countries,
claim some pretty screwy wiring schemes for the 'neutral' in their wiring. I have no idea if those people knew what
they were talking about, or if there might be some creative-wiring going on locally to contend with their available power suppliers. For us, we don't switch a neutral, ... but in Swaziland, not knowing what Stardian101 actually HAS,
I'd just be guessing about what's going on with his problem.
I think all of us are doing what we can to help. But the unknowns here might be different from what we expect.

 

[Bluejets]

Neutral and Earth are supposed to be connected together. The light switch is supposed to connect and disconnect the Line wire not the Neutral.

They are (in some countries....MEN) but they will get a voltage difference in many instances.
To understand this I guess one has to be involved with the trade for many years.
Depends on several conditions, a couple being poor neutral connections at point of entry (or other) or poor conductivity in and around earth electrode allowing neutral voltage to rise above earth potential, or perhaps even poorly installed equipment.
The reference to fluro was to try to make it easier for the op to grasp as it is a simpler circuit overall.