I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

What could cause this?

Perce

On Apr 5, 4:20�pm, "Percival P. Cassidy"
wrote:
I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

What could cause this?

Perce

its the meter, take a walk around high sensitivity meters will show 60
volts under the neighborhood power line........

connect a 100 watt light bulb with the meter voltage will go away.

relax yours must be one of the most frequent questions asked.

On Sun, 05 Apr 2009 16:20:03 -0400, "Percival P. Cassidy"
wrote:

I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

LED? You don't mean complact fluorescent? I havent' seen LEDs that
fit wthout changes.

But in the kitchen with a timer in place of the wall switch, I
couldn't get my CFL to turn off. Do you have a timer in the circuit.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

A timer in each room, and on lamps, seems unlikely.

What could cause this?

Perce

On Apr 5, 3:39*pm, wrote:
On Sun, 5 Apr 2009 13:43:59 -0700 (PDT), bob haller
wrote:



On Apr 5, 4:20?pm, "Percival P. Cassidy"
wrote:
I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

What could cause this?

Perce

its the meter, take a walk around high sensitivity meters will show 60
volts under the neighborhood power line........

connect a 100 watt light bulb with the meter voltage will go away.

relax yours must be one of the most frequent questions asked.

While the meter reading may not be accurate if the meter is a digital
type, he said the LED bulbs do not shut off completely and glow dimly.
This indicates that there is indeed some electrical leakage bleeding
over from somewhere. *I suspect a bad neutral connection and the
leakage is being fed back most likely thru an appliance or the
filament of a lightbulb somewhere downstream. *

I'd remove every lightbulb and anything plugged into every outlet on
that circuit. *The bulb or appliance that stops the leakage is likely
the fixture with the bad connection. *If you can not find it in this
manner, open every fixture/outlet on this circuit and check for bad
connections. *Use an ANALOG meter for testing.

I agree, sounds like a bad ground (neutral)

mm wrote:
On Sun, 05 Apr 2009 16:20:03 -0400, "Percival P. Cassidy"
wrote:

I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

LED? You don't mean complact fluorescent? I havent' seen LEDs that
fit wthout changes.

But in the kitchen with a timer in place of the wall switch, I
couldn't get my CFL to turn off. Do you have a timer in the circuit.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

A timer in each room, and on lamps, seems unlikely.

What could cause this?

Perce

I'm going to guess here that you have
some kind of electronic switch, i.e. a
dimmer or something similar. As long as
there is enough voltage to turn on the
LEDs, a small leakage current from an
electronic switch could make them glow
dimly.

On Sun, 05 Apr 2009 22:27:56 -0400, Art Todesco
wrote:

mm wrote:
On Sun, 05 Apr 2009 16:20:03 -0400, "Percival P. Cassidy"
wrote:

I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

LED? You don't mean complact fluorescent? I havent' seen LEDs that
fit wthout changes.

But in the kitchen with a timer in place of the wall switch, I
couldn't get my CFL to turn off. Do you have a timer in the circuit.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

A timer in each room, and on lamps, seems unlikely.

What could cause this?

Perce

I'm going to guess here that you have
some kind of electronic switch, i.e. a

Yes, a timer, an electronic on/off timer.

dimmer or something similar. As long as
there is enough voltage to turn on the
LEDs, a small leakage current from an
electronic switch could make them glow
dimly.

On Sun, 05 Apr 2009 16:20:03 -0400, Percival P. Cassidy wrote:
I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

48V at high impedance means absolutely nothing.

On Sun, 05 Apr 2009 22:32:37 -0400, mm
wrote:



I'm going to guess here that you have
some kind of electronic switch, i.e. a

Yes, a timer, an electronic on/off timer.

dimmer or something similar. As long as
there is enough voltage to turn on the
LEDs, a small leakage current from an
electronic switch could make them glow
dimly.

That's it. I bet your timer was designed to not require a neutral.
As such, it has to draw a little current through the lamps to power
itself even when off. x-10 switches are notorious for that, but any
electronic device that gets wired in place of a switch and does not
require a neutral connection will do it. Usually placing a small
incondescent bulb (like a 7 watt night light bulb) or a resister in
parallel with the LED's will solve the issue. Or, get a different
timer that requires a neutral (if the box in question has a neutral
wire in it, Or, get rid of the timer if you don't really need it.

On Sun, 05 Apr 2009 22:44:55 -0500, AZ Nomad
wrote Re 48 volts with switch
off!:

On Sun, 05 Apr 2009 16:20:03 -0400, Percival P. Cassidy wrote:
I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

48V at high impedance means absolutely nothing.


Why is that?

On Apr 6, 5:38*am, wrote:
On Sun, 05 Apr 2009 22:32:37 -0400, mm
wrote:



I'm going to guess here that you have
some kind of electronic switch, i.e. a

Yes, a timer, an electronic on/off timer.

dimmer or something similar. *As long as
there is enough voltage to turn on the
LEDs, a small leakage current from an
electronic switch could make them glow
dimly.

That's it. *I bet your timer was designed to not require a neutral.
As such, it has to draw a little current through the lamps to power
itself even when off. *x-10 switches are notorious for that, but any
electronic device that gets wired in place of a switch and does not
require a neutral connection will do it. *Usually placing a small
incondescent bulb (like a 7 watt night light bulb) or a resister *in
parallel with the LED's will solve the issue. * Or, get a different
timer that requires a neutral (if the box in question has a neutral
wire in it, *Or, get rid of the timer if you don't really need it.

Yes, agree that the electronic timer is what's causing the bulbs to
light dimly. Most of those type devices are designed to work without
a neutral, so they rely on some very small current always flowing.
In the case of incandescent bulbs, it's not a problem. But CFLs,
LEDs take so little current, it's enought o start to light them. If
you look at the data sheet for that electronic timer/switch it most
likely says it's for incandescent use only.

AZ Nomad wrote:
On Sun, 05 Apr 2009 16:20:03 -0400, Percival P. Cassidy wrote:
I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

48V at high impedance means absolutely nothing.
Except to make LEDs glow dimly when the
switch is off!

I agree its the timer. years ago one caused me wierd troubles so I
tossed it and went with a old neutral style with mechanical switch it
still working fine today. at least 15 years after install

Which one? The neutral wire is white, the ground is bare.
One or the other, please.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"gnu / linux" wrote in message
...


I agree, sounds like a bad ground (neutral)

Cause you can have 48 volts, at zero load. But not enough
working amps to do anything useful.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Caesar Romano" wrote in message
...
On Sun, 05 Apr 2009 22:44:55 -0500, AZ Nomad
wrote Re 48 volts with
switch
off!:


48V at high impedance means absolutely nothing.


Why is that?

On 04/05/09 05:21 pm mm wrote:

I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

LED? You don't mean complact fluorescent? I havent' seen LEDs that
fit wthout changes.

LED screw-in replacements for incandescent bulbs. Our local Sam's Club
has a few different varieties of them. I have a few that are claimed to
be 45W equivalent in light output for a consumption of 3.5W. The light
is somewhat blue, but it's fine for my purposes and works fine as a
replacement for the previous 50W incandescent flood.


But in the kitchen with a timer in place of the wall switch, I
couldn't get my CFL to turn off. Do you have a timer in the circuit.

No timer. Just an ordinary mechanical wall switch.

Perce

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

A timer in each room, and on lamps, seems unlikely.

What could cause this?

On 04/05/09 10:27 pm Art Todesco wrote:

I replaced some existing incandescent bulbs by LED bulbs, then
noticed that they do not switch off completely but still glow dimly.

LED? You don't mean complact fluorescent? I havent' seen LEDs that
fit wthout changes.

But in the kitchen with a timer in place of the wall switch, I
couldn't get my CFL to turn off. Do you have a timer in the circuit.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be
OK -- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

A timer in each room, and on lamps, seems unlikely.
What could cause this?

I'm going to guess here that you have some kind of electronic switch,
i.e. a dimmer or something similar. As long as there is enough voltage
to turn on the LEDs, a small leakage current from an electronic switch
could make them glow dimly.

No. Regular "mechanical" wall switch.

Perce

On 04/06/09 05:38 am wrote:

I'm going to guess here that you have
some kind of electronic switch, i.e. a
Yes, a timer, an electronic on/off timer.

dimmer or something similar. As long as
there is enough voltage to turn on the
LEDs, a small leakage current from an
electronic switch could make them glow
dimly.

That's it. I bet your timer was designed to not require a neutral.
As such, it has to draw a little current through the lamps to power
itself even when off. x-10 switches are notorious for that, but any
electronic device that gets wired in place of a switch and does not
require a neutral connection will do it. Usually placing a small
incondescent bulb (like a 7 watt night light bulb) or a resister in
parallel with the LED's will solve the issue. Or, get a different
timer that requires a neutral (if the box in question has a neutral
wire in it, Or, get rid of the timer if you don't really need it.

No timer or dimmer. A regular wall switch.

Perce

On 04/05/09 10:32 pm mm wrote:

I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.
LED? You don't mean complact fluorescent? I havent' seen LEDs that
fit wthout changes.

But in the kitchen with a timer in place of the wall switch, I
couldn't get my CFL to turn off. Do you have a timer in the circuit.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.
A timer in each room, and on lamps, seems unlikely.

What could cause this?

I'm going to guess here that you have
some kind of electronic switch, i.e. a

Yes, a timer, an electronic on/off timer.

dimmer or something similar. As long as
there is enough voltage to turn on the
LEDs, a small leakage current from an
electronic switch could make them glow
dimly.

No timer or dimmer. A regular on/off wall switch.

Perce

On 04/06/09 08:35 am bob haller wrote:

I agree its the timer. years ago one caused me wierd troubles so I
tossed it and went with a old neutral style with mechanical switch it
still working fine today. at least 15 years after install

No timer or dimmer. A regular on/off wall switch.

Perce

On Mon, 06 Apr 2009 06:32:43 -0500, Caesar Romano wrote:
On Sun, 05 Apr 2009 22:44:55 -0500, AZ Nomad
wrote Re 48 volts with switch
off!:

On Sun, 05 Apr 2009 16:20:03 -0400, Percival P. Cassidy wrote:
I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

48V at high impedance means absolutely nothing.


Why is that?

It doesn't indicate any current flow or even potential for current flow.
Voltage alone, measured with a high impedance meter is little different
than static electricity. Leakage from capacatance between insulators
will throw off a high impedance meter.

Put a 1K resistor on it, and the voltage will drop to zero.

Percival P. Cassidy wrote:
I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

What could cause this?

Perce

Get yourself a "Y" socket adaptor like this:

http://tinyurl.com/d8oha9

With the wall switch OFF, screw the adaptor into the socket of interest
and put an LED bulb in one side and measure the "switch off" voltage in
the open socket.

Betcha it'll be a lot less than 48 volts then.

Now, screw a regular incandescent bulb into the open socket.

If the LED bulb stops glowing when the incandescent is put in then I
agree with the other posters who said that capacitive coupling, probably
in a "switch leg" piece of cable is letting enough current run through
the LED bulb to make it glow.

You could experiment by screwing a plug adaptor like this:

http://tinyurl.com/dm2rvz

into the open socket so you could easily stick the leads of different
value carbon resistors into its slots to see if you could get the LEDs
to stop glowing with a resistance value high enough so that if it was
permenantly wired across the socket it wouldn't generate much sensible heat.

I'd start with a one watt 20,000 ohm carbon resistor and see if that
works. If it does, try an even higher resistance, say 100,000 ohms. If
you can get the LEDs to stop glowing with a resistor of 20,000 ohms or
greater, then you could wire resistors of that size directly across the
fixture socket(s).

Let us all know how you make out.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

On 04/06/09 01:19 pm Jeff Wisnia wrote:

I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be
OK -- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

What could cause this?

Get yourself a "Y" socket adaptor like this:

http://tinyurl.com/d8oha9

With the wall switch OFF, screw the adaptor into the socket of interest
and put an LED bulb in one side and measure the "switch off" voltage in
the open socket.

Betcha it'll be a lot less than 48 volts then.

I don't need the "Y" adapter, because this is a multi-lamp setup anyway:
three lamp fittings on a track. The 48V reading is with identical LED
bulbs in the other two fittings.

Now, screw a regular incandescent bulb into the open socket.

If the LED bulb stops glowing when the incandescent is put in then I
agree with the other posters who said that capacitive coupling, probably
in a "switch leg" piece of cable is letting enough current run through
the LED bulb to make it glow.

Yes, with a regular incandescent bulb in one fitting, the LED bulbs in
the other two fittings do not glow.

You could experiment by screwing a plug adaptor like this:

http://tinyurl.com/dm2rvz

into the open socket so you could easily stick the leads of different
value carbon resistors into its slots to see if you could get the LEDs
to stop glowing with a resistance value high enough so that if it was
permenantly wired across the socket it wouldn't generate much sensible
heat.

I'd start with a one watt 20,000 ohm carbon resistor and see if that
works. If it does, try an even higher resistance, say 100,000 ohms. If
you can get the LEDs to stop glowing with a resistor of 20,000 ohms or
greater, then you could wire resistors of that size directly across the
fixture socket(s).

That's an idea. I'll try it when I can get to the store and buy those items.

Let us all know how you make out.

I will.

Perce

On 04/05/09 04:43 pm bob haller wrote:

I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

What could cause this?

its the meter, take a walk around high sensitivity meters will show 60
volts under the neighborhood power line........

connect a 100 watt light bulb with the meter voltage will go away.

relax yours must be one of the most frequent questions asked.

OK, but

(1) there are no overhead power lines within a mile. Walking around the
house with that meter and a lead trailing like an antenna I see not even
a 1 volt reading.

(2) It's a pain that the LED lights don't switch off completely. The
voltage with the switch off is sufficient to keep them glowing dimly.
Perhaps replacing one of the bulbs by a low-wattage incandescent would
hold the voltage down, but that offsets the power saving benefit of the
LEDs.

Perce

On 04/05/09 05:21 pm mm wrote:

I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

LED? You don't mean complact fluorescent? I havent' seen LEDs that
fit wthout changes.

LED screw-in replacements for incandescent bulbs. Our local Sam's Club
has a few different varieties of them. I have a few that are claimed to
be 45W equivalent in light output for a consumption of 3.5W. The light
is somewhat blue, but it's fine for my purposes and works fine as a
replacement for the previous 50W incandescent flood.


But in the kitchen with a timer in place of the wall switch, I
couldn't get my CFL to turn off. Do you have a timer in the circuit.

No timer. Just an ordinary mechanical wall switch.

Perce

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

A timer in each room, and on lamps, seems unlikely.

What could cause this?

Percival P. Cassidy wrote:
On 04/05/09 10:27 pm Art Todesco wrote:

I replaced some existing incandescent bulbs by LED bulbs, then
noticed that they do not switch off completely but still glow dimly.

LED? You don't mean complact fluorescent? I havent' seen LEDs that
fit wthout changes.

But in the kitchen with a timer in place of the wall switch, I
couldn't get my CFL to turn off. Do you have a timer in the circuit.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be
OK -- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

A timer in each room, and on lamps, seems unlikely.
What could cause this?

I'm going to guess here that you have some kind of electronic switch,
i.e. a dimmer or something similar. As long as there is enough voltage
to turn on the LEDs, a small leakage current from an electronic switch
could make them glow dimly.

No. Regular "mechanical" wall switch.

Perce

Possibly a lighted mechanical wall switch?

"Percival P. Cassidy" wrote in message
...
On 04/06/09 08:35 am bob haller wrote:

I agree its the timer. years ago one caused me wierd troubles so I
tossed it and went with a old neutral style with mechanical switch it
still working fine today. at least 15 years after install

No timer or dimmer. A regular on/off wall switch.

Perce


Try taking one of the wires off the switch , or replace the switch. It may
be possiable the switch has developed some leakage across it. Maybe someone
tried cleaning it and got some fluid insided the switch.

On Mon, 06 Apr 2009 17:05:08 -0400, "Percival P. Cassidy"
wrote:

On 04/05/09 04:43 pm bob haller wrote:

I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

What could cause this?

its the meter, take a walk around high sensitivity meters will show 60
volts under the neighborhood power line........

connect a 100 watt light bulb with the meter voltage will go away.

relax yours must be one of the most frequent questions asked.

OK, but

(1) there are no overhead power lines within a mile. Walking around the
house with that meter and a lead trailing like an antenna I see not even
a 1 volt reading.

(2) It's a pain that the LED lights don't switch off completely. The
voltage with the switch off is sufficient to keep them glowing dimly.
Perhaps replacing one of the bulbs by a low-wattage incandescent would
hold the voltage down, but that offsets the power saving benefit of the
LEDs.

Perce


Cover the bulb - make it completely dark - the voltage will likely go
away. You are LIKELY getting a DC voltage FROM the light because an
LED is ALSO a photocell. An LED will produce a DC voltage when exposed
to light.
Green ones are Gallium Phosphide and make 1.65 to 1.74 volts each.
Not sure what the white ones are and what voltage they produce but I
think they are Indium Gallium Nitride - so likely around the same
output.

On 04/06/09 08:21 pm Art Todesco wrote:

I replaced some existing incandescent bulbs by LED bulbs, then
noticed that they do not switch off completely but still glow dimly.

LED? You don't mean complact fluorescent? I havent' seen LEDs that
fit wthout changes.

But in the kitchen with a timer in place of the wall switch, I
couldn't get my CFL to turn off. Do you have a timer in the circuit.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be
OK -- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

A timer in each room, and on lamps, seems unlikely.
What could cause this?

I'm going to guess here that you have some kind of electronic switch,
i.e. a dimmer or something similar. As long as there is enough voltage
to turn on the LEDs, a small leakage current from an electronic switch
could make them glow dimly.

No. Regular "mechanical" wall switch.

Possibly a lighted mechanical wall switch?

No light in the switch.

Perce

On 04/06/09 10:43 pm wrote:

I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

What could cause this?
its the meter, take a walk around high sensitivity meters will show 60
volts under the neighborhood power line........

connect a 100 watt light bulb with the meter voltage will go away.

relax yours must be one of the most frequent questions asked.
OK, but

(1) there are no overhead power lines within a mile. Walking around the
house with that meter and a lead trailing like an antenna I see not even
a 1 volt reading.

(2) It's a pain that the LED lights don't switch off completely. The
voltage with the switch off is sufficient to keep them glowing dimly.
Perhaps replacing one of the bulbs by a low-wattage incandescent would
hold the voltage down, but that offsets the power saving benefit of the
LEDs.

Cover the bulb - make it completely dark - the voltage will likely go
away. You are LIKELY getting a DC voltage FROM the light because an
LED is ALSO a photocell. An LED will produce a DC voltage when exposed
to light.
Green ones are Gallium Phosphide and make 1.65 to 1.74 volts each.
Not sure what the white ones are and what voltage they produce but I
think they are Indium Gallium Nitride - so likely around the same
output.

It's only because I walked into a supposedly dark room that I discovered
that the LEDs were not totally dark.

There was no ambient light that could have caused any photovoltaic effect.

Perce

On Mon, 06 Apr 2009 22:43:57 -0400, wrote:

On Mon, 06 Apr 2009 17:05:08 -0400, "Percival P. Cassidy"
wrote:

On 04/05/09 04:43 pm bob haller wrote:

I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

What could cause this?

its the meter, take a walk around high sensitivity meters will show 60
volts under the neighborhood power line........

connect a 100 watt light bulb with the meter voltage will go away.

relax yours must be one of the most frequent questions asked.

OK, but

(1) there are no overhead power lines within a mile. Walking around the
house with that meter and a lead trailing like an antenna I see not even
a 1 volt reading.

(2) It's a pain that the LED lights don't switch off completely. The
voltage with the switch off is sufficient to keep them glowing dimly.
Perhaps replacing one of the bulbs by a low-wattage incandescent would
hold the voltage down, but that offsets the power saving benefit of the
LEDs.

Perce


Cover the bulb - make it completely dark - the voltage will likely go
away. You are LIKELY getting a DC voltage FROM the light because an
LED is ALSO a photocell. An LED will produce a DC voltage when exposed
to light.
Green ones are Gallium Phosphide and make 1.65 to 1.74 volts each.
Not sure what the white ones are and what voltage they produce but I
think they are Indium Gallium Nitride - so likely around the same
output.


And remember - White LEDs also have a phosphorescent material in them
that makes white light from blue - the Phospor actually produces a
yellow light.

On Apr 5, 4:20*pm, "Percival P. Cassidy"
wrote:
I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

What could cause this?

Perce

I got the same results when I put some LED lights on a light activated
switch that used a solidstate switch. The fix was to change it to one
that used an internal relay. These can be hard to find.

Jimmie

Percival P. Cassidy wrote:
On 04/06/09 08:21 pm Art Todesco wrote:

I replaced some existing incandescent bulbs by LED bulbs, then
noticed that they do not switch off completely but still glow dimly.

LED? You don't mean complact fluorescent? I havent' seen LEDs that
fit wthout changes.

But in the kitchen with a timer in place of the wall switch, I
couldn't get my CFL to turn off. Do you have a timer in the circuit.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be
OK -- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

A timer in each room, and on lamps, seems unlikely.
What could cause this?

I'm going to guess here that you have some kind of electronic switch,
i.e. a dimmer or something similar. As long as there is enough voltage
to turn on the LEDs, a small leakage current from an electronic switch
could make them glow dimly.

No. Regular "mechanical" wall switch.

Possibly a lighted mechanical wall switch?

No light in the switch.

Perce

O well, I just thought of that. BTW,
did you try disconnecting the lamp?
Maybe the phosphors are still glowing a
little .... I know, that's a big
stretch!

Percival P. Cassidy wrote:
On 04/06/09 01:19 pm Jeff Wisnia wrote:

I replaced some existing incandescent bulbs by LED bulbs, then noticed
that they do not switch off completely but still glow dimly.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be
OK -- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

What could cause this?


Get yourself a "Y" socket adaptor like this:

http://tinyurl.com/d8oha9

With the wall switch OFF, screw the adaptor into the socket of interest
and put an LED bulb in one side and measure the "switch off" voltage in
the open socket.

Betcha it'll be a lot less than 48 volts then.


I don't need the "Y" adapter, because this is a multi-lamp setup anyway:
three lamp fittings on a track. The 48V reading is with identical LED
bulbs in the other two fittings.

Oopsie, I assumed 48 volts with NO bulb(s) in the socket(s).

Have you tried that (No bulbs, but with the same meter) and if so does
the voltage read higher than 48?


Now, screw a regular incandescent bulb into the open socket.

If the LED bulb stops glowing when the incandescent is put in then I
agree with the other posters who said that capacitive coupling, probably
in a "switch leg" piece of cable is letting enough current run through
the LED bulb to make it glow.


Yes, with a regular incandescent bulb in one fitting, the LED bulbs in
the other two fittings do not glow.

Well, that shoots the phosphorescent glow idea down even more. G


You could experiment by screwing a plug adaptor like this:

http://tinyurl.com/dm2rvz

into the open socket so you could easily stick the leads of different
value carbon resistors into its slots to see if you could get the LEDs
to stop glowing with a resistance value high enough so that if it was
permenantly wired across the socket it wouldn't generate much sensible
heat.

I'd start with a one watt 20,000 ohm carbon resistor and see if that
works. If it does, try an even higher resistance, say 100,000 ohms. If
you can get the LEDs to stop glowing with a resistor of 20,000 ohms or
greater, then you could wire resistors of that size directly across the
fixture socket(s).


That's an idea. I'll try it when I can get to the store and buy those
items.

Let us all know how you make out.


I will.

Perce



--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

Percival P. Cassidy wrote:
On 04/06/09 01:19 pm Jeff Wisnia wrote:

If the LED bulb stops glowing when the incandescent is put in then I
agree with the other posters who said that capacitive coupling, probably
in a "switch leg" piece of cable is letting enough current run through
the LED bulb to make it glow.

Yes, with a regular incandescent bulb in one fitting, the LED bulbs in
the other two fittings do not glow.

I agree with Jeff (and others).

A common test device is a simple neon light with 2 tests leads. If you
plug one lead into the hot side of a receptacle and hold the other lead
the neon light will light up (very dimly). This works if you are
isolated with only extremely high resistance path to anywhere. There is
a *very* small capacitance from your body to ‘the world’.

The capacitance between parallel wires is far higher and could drive a
small current to the LED bulbs and produce a small amount of light.

bud-- wrote:
Percival P. Cassidy wrote:

On 04/06/09 01:19 pm Jeff Wisnia wrote:


If the LED bulb stops glowing when the incandescent is put in then I
agree with the other posters who said that capacitive coupling, probably
in a "switch leg" piece of cable is letting enough current run through
the LED bulb to make it glow.


Yes, with a regular incandescent bulb in one fitting, the LED bulbs in
the other two fittings do not glow.


I agree with Jeff (and others).

A common test device is a simple neon light with 2 tests leads. If you
plug one lead into the hot side of a receptacle and hold the other lead
the neon light will light up (very dimly). This works if you are
isolated with only extremely high resistance path to anywhere. There is
a *very* small capacitance from your body to ‘the world’.

Yup, that human body capacitance is commonly accepted as being 100
picofarads for an avergage sized homo sapiens.

That's the capacitance which stores a high voltage charge when you
scuffle across a rug, and then discharges to something else (like your
cat's nose) when you get too close to it.

Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

The capacitance between parallel wires is far higher and could drive a
small current to the LED bulbs and produce a small amount of light.

On 04/06/09 11:03 pm I wrote:

I replaced some existing incandescent bulbs by LED bulbs, then
noticed that they do not switch off completely but still glow dimly.

LED? You don't mean compact fluorescent? I havent' seen LEDs that
fit wthout changes.

But in the kitchen with a timer in place of the wall switch, I
couldn't get my CFL to turn off. Do you have a timer in the circuit.

Checking the voltage at the lamp socket with a high-resistance
electronic multimeter, I get a reading of 48v!! A few volts might be
OK -- induction, stray voltages, etc., but 48V!!!

This occurs in two different rooms, but I think the various lighting
circuits are all connected to one breaker.

I hadn't measured the voltage in the second room, but I assumed that the
glowing LEDs after switching off had the same cause. In fact this was
simply a brief "decay time," probably as a capacitor discharged.

A timer in each room, and on lamps, seems unlikely.
What could cause this?

I'm going to guess here that you have some kind of electronic switch,
i.e. a dimmer or something similar. As long as there is enough voltage
to turn on the LEDs, a small leakage current from an electronic switch
could make them glow dimly.

No. Regular "mechanical" wall switch.

Possibly a lighted mechanical wall switch?

No light in the switch.

It turns out that it was a lighted switch after all -- but no light had
been visible in the switch with the CFL bulbs that I replaced by LED.
And even when I had the switch hanging out of the wall. the "Lighted"
label was on the side away from me.

Perce