I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Seán Ó Leathlóbhair

Seán O'Leathlóbhair wrote in message
ups.com...
I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Seán Ó Leathlóbhair


It may not be a switch problem but more seriously an animal , usually
squirrel or mouse or rat has chewed the insulation along the wires going to
the switch, now with charred insulation, so passing a bit of current - so
get the wiring leakage/visually checked. Especially if you've had any
unexplained fuses blowing or history of animal noises in loft or floor
spaces.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

On 25 Jun, 15:20, "N Cook" wrote:
Seán O'Leathlóbhair wrote in message

ups.com...
I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Seán Ó Leathlóbhair

It may not be a switch problem but more seriously an animal , usually
squirrel or mouse or rat has chewed the insulation along the wires going to
the switch, now with charred insulation, so passing a bit of current - so
get the wiring leakage/visually checked. Especially if you've had any
unexplained fuses blowing or history of animal noises in loft or floor
spaces.


Thanks for the advice.

We had some fuse problems many years ago but not on the lighting
circuits. The problem was traced (by a proper electrician) to the
ancient (bakelite) fuse box. It was replaced with a modern fuse box.
The wiring was tested (but not completely inspected) at the time.
Since then, we have not had any fuse problems. That was about 10
years ago.

I am not aware of any animal problems in the loft but, of course, that
does not mean that there have not been any. Access to the loft is
difficult since it is very small but not quite impossible. I will
squeeze myself in and have a look.

--
Seán Ó Leathlóbhair

On Jun 25, 10:03 am, Seán O'Leathlóbhair wrote:
I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Seán Ó Leathlóbhair

Try the buld in another location. Give us moe information on the bulb.

Bruce

On 25 Jun, 15:21, BH wrote:
On Jun 25, 10:03 am, Seán O'Leathlóbhair wrote:





I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Seán Ó Leathlóbhair

Try the buld in another location. Give us moe information on the bulb.


Thanks.

Normally, I would immediately try to isolate the cause by moving
things around but, in this case, I dismissed the bulb as the problem
since I thought that if the switch was passing nothing when off (as it
should) then there was no way the bulb could do what it is doing. If
the bulb is at fault then it is not the only fault (or so I assumed at
any rate).

The brand of the bulb is Philips but I cannot tell you more until I
get home and look at it. I will post again later with fuller details
and the result of a test in another location.

--
Seán Ó Leathlóbhair

Seán O'Leathlóbhair wrote:
On 25 Jun, 15:21, BH wrote:
On Jun 25, 10:03 am, Seán O'Leathlóbhair wrote:





I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.
I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.
When it is switched on, it works as expected.
When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.
I have a few questions:
What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.
Is it safe?
Will it wear out the bulb very fast?
Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).
Might I have to replace the wiring? (Much harder than just replacing
the switches)
--
Seán Ó Leathlóbhair
Try the buld in another location. Give us moe information on the bulb.


Thanks.

Normally, I would immediately try to isolate the cause by moving
things around but, in this case, I dismissed the bulb as the problem
since I thought that if the switch was passing nothing when off (as it
should) then there was no way the bulb could do what it is doing. If
the bulb is at fault then it is not the only fault (or so I assumed at
any rate).

The brand of the bulb is Philips but I cannot tell you more until I
get home and look at it. I will post again later with fuller details
and the result of a test in another location.

Hi...

Can't help wondering - it's not possible that one of those
"switches" is a dimmer, is it?

Take care.

Ken

On 25 Jun, 15:39, Ken Weitzel wrote:
Seán O'Leathlóbhair wrote:
On 25 Jun, 15:21, BH wrote:
On Jun 25, 10:03 am, Seán O'Leathlóbhair wrote:

I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.
I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.
When it is switched on, it works as expected.
When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.
I have a few questions:
What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.
Is it safe?
Will it wear out the bulb very fast?
Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).
Might I have to replace the wiring? (Much harder than just replacing
the switches)
--
Seán Ó Leathlóbhair
Try the buld in another location. Give us moe information on the bulb.

Thanks.

Normally, I would immediately try to isolate the cause by moving
things around but, in this case, I dismissed the bulb as the problem
since I thought that if the switch was passing nothing when off (as it
should) then there was no way the bulb could do what it is doing. If
the bulb is at fault then it is not the only fault (or so I assumed at
any rate).

The brand of the bulb is Philips but I cannot tell you more until I
get home and look at it. I will post again later with fuller details
and the result of a test in another location.

Hi...

Can't help wondering - it's not possible that one of those
"switches" is a dimmer, is it?

Take care.


A good question but no.

It is a landing light. There are three switches, one at each end and
a third in the middle where a small corridor from the bathroom joins
the landing. All simple on off switches (well they must be changeover
switches but, from the user's point of view, they are just on off).

--
Seán Ó Leathlóbhair

Seán O'Leathlóbhair wrote:
On 25 Jun, 15:39, Ken Weitzel wrote:
Seán O'Leathlóbhair wrote:
On 25 Jun, 15:21, BH wrote:
On Jun 25, 10:03 am, Seán O'Leathlóbhair wrote:
I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.
I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.
When it is switched on, it works as expected.
When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.
I have a few questions:
What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.
Is it safe?
Will it wear out the bulb very fast?
Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).
Might I have to replace the wiring? (Much harder than just replacing
the switches)
--
Seán Ó Leathlóbhair
Try the buld in another location. Give us moe information on the bulb.
Thanks.
Normally, I would immediately try to isolate the cause by moving
things around but, in this case, I dismissed the bulb as the problem
since I thought that if the switch was passing nothing when off (as it
should) then there was no way the bulb could do what it is doing. If
the bulb is at fault then it is not the only fault (or so I assumed at
any rate).
The brand of the bulb is Philips but I cannot tell you more until I
get home and look at it. I will post again later with fuller details
and the result of a test in another location.
Hi...

Can't help wondering - it's not possible that one of those
"switches" is a dimmer, is it?

Take care.


A good question but no.

It is a landing light. There are three switches, one at each end and
a third in the middle where a small corridor from the bathroom joins
the landing. All simple on off switches (well they must be changeover
switches but, from the user's point of view, they are just on off).


Sounds like leakage to me, there may be a measurable voltage floating on
the neutral. I has a similar problem with fluorescent emergency lights
last year. If you are in the UK it might be an earthing fault.

Ron(UK)

On Mon, 25 Jun 2007 07:45:29 -0700, Seán O'Leathlóbhair
wrote:

On 25 Jun, 15:39, Ken Weitzel wrote:
Seán O'Leathlóbhair wrote:
On 25 Jun, 15:21, BH wrote:
On Jun 25, 10:03 am, Seán O'Leathlóbhair wrote:

I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.
I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.
When it is switched on, it works as expected.
When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.
I have a few questions:
What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.
Is it safe?
Will it wear out the bulb very fast?
Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).
Might I have to replace the wiring? (Much harder than just replacing
the switches)
--
Seán Ó Leathlóbhair
Try the buld in another location. Give us moe information on the bulb.

Thanks.

Normally, I would immediately try to isolate the cause by moving
things around but, in this case, I dismissed the bulb as the problem
since I thought that if the switch was passing nothing when off (as it
should) then there was no way the bulb could do what it is doing. If
the bulb is at fault then it is not the only fault (or so I assumed at
any rate).

The brand of the bulb is Philips but I cannot tell you more until I
get home and look at it. I will post again later with fuller details
and the result of a test in another location.

Hi...

Can't help wondering - it's not possible that one of those
"switches" is a dimmer, is it?

Take care.


A good question but no.

It is a landing light. There are three switches, one at each end and
a third in the middle where a small corridor from the bathroom joins
the landing. All simple on off switches (well they must be changeover
switches but, from the user's point of view, they are just on off).

Your switches are wired wrong (they are switching the neutral (or
cold) side of the line, not the hot side. As well, you seem to have a
leakage problem in the circuit as well. This leakage could be a switch
or some other device or part.

First step is to make 100% sure the switches are in the hot side of
the circuit. That will likely solve your problem immediately. I'd
guess there is a chance much of your house is not wired correctly from
your description...

Not sure what building codes/wriing codes you have in the UK, but in
the US this circuit would not have passed a building inspector.

=?iso-8859-1?B?U2XhbiBPJ0xlYXRobPNiaGFpcg==?= writes:

On 25 Jun, 15:39, Ken Weitzel wrote:
Se=E1n O'Leathl=F3bhair wrote:
On 25 Jun, 15:21, BH wrote:
On Jun 25, 10:03 am, Se=E1n O'Leathl=F3bhair wrot=
e:

I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.
I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.
When it is switched on, it works as expected.
When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.
I have a few questions:
What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.
Is it safe?
Will it wear out the bulb very fast?
Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).
Might I have to replace the wiring? (Much harder than just replacing
the switches)
--
Se=E1n =D3 Leathl=F3bhair
Try the buld in another location. Give us moe information on the bulb.

Thanks.

Normally, I would immediately try to isolate the cause by moving
things around but, in this case, I dismissed the bulb as the problem
since I thought that if the switch was passing nothing when off (as it
should) then there was no way the bulb could do what it is doing. If
the bulb is at fault then it is not the only fault (or so I assumed at
any rate).

The brand of the bulb is Philips but I cannot tell you more until I
get home and look at it. I will post again later with fuller details
and the result of a test in another location.

Hi...

Can't help wondering - it's not possible that one of those
"switches" is a dimmer, is it?

Take care.


A good question but no.

It is a landing light. There are three switches, one at each end and
a third in the middle where a small corridor from the bathroom joins
the landing. All simple on off switches (well they must be changeover
switches but, from the user's point of view, they are just on off).

And none are lighted switches?

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
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| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

Seán O'Leathlóbhair wrote:
I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.


I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Seán Ó Leathlóbhair


On a cold wet miserable winter day in the early 70's. I was
troubleshooting a newish car, that wouldn't start, that had just been
serviced by a car dealership. a few days before. To cut a long story
short, they lubricated the Point Breaker mechanism with a clear Grease
that they probably used for years with no problems ! With 2 to 6 Amps
flowing, the contact mechanism probably cooked off any wet or
conductive grease. With the newer Hybrid Transistor switched points the
DAMP grease appeared as a Dead Short to the few milliamps required to
actuate the Transistor.

I would suspect the switches (All three) are lubricated with a grease
that is conductive enough read (dirty enough)to cause the problems
indicated !

The quick and dirty, to clear the excess grease is to replace the lamp
in question with a 60 - 100 watt bulb and switch On and Off a few
times. in the Off position any conductive grease will be burned away.

Any fire Hazard, Not likely, after all these switches were manufactured
and sold for years lubricated just like this, besides we are talking
about a drop or two grease total ! If you are worried, replace the
switches.

If this doesn't clear the problem than you may have exessive
capacitative coupling between the various conductors due to the
three-way switching, under a very light load !

Yukio YANO

On 25 Jun, 19:35, Yukio YANO wrote:
Seán O'Leathlóbhair wrote:
I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Seán Ó Leathlóbhair

On a cold wet miserable winter day in the early 70's. I was
troubleshooting a newish car, that wouldn't start, that had just been
serviced by a car dealership. a few days before. To cut a long story
short, they lubricated the Point Breaker mechanism with a clear Grease
that they probably used for years with no problems ! With 2 to 6 Amps
flowing, the contact mechanism probably cooked off any wet or
conductive grease. With the newer Hybrid Transistor switched points the
DAMP grease appeared as a Dead Short to the few milliamps required to
actuate the Transistor.

I would suspect the switches (All three) are lubricated with a grease
that is conductive enough read (dirty enough)to cause the problems
indicated !

The quick and dirty, to clear the excess grease is to replace the lamp
in question with a 60 - 100 watt bulb and switch On and Off a few
times. in the Off position any conductive grease will be burned away.

I may try that since it is easy. The previous bulb was a 40W
incandescent but we would not normally switch it on and off rapidly.
Would cleaning the contacts with something like WD40 be a good or bad
idea? I have never used this on mains voltage devices.

Any fire Hazard, Not likely, after all these switches were manufactured
and sold for years lubricated just like this, besides we are talking
about a drop or two grease total ! If you are worried, replace the
switches.

If this doesn't clear the problem than you may have exessive
capacitative coupling between the various conductors due to the
three-way switching, under a very light load !

--
Seán Ó Leathlóbhair

Seán O'Leathlóbhair wrote:

Would cleaning the contacts with something like WD40 be a good or bad
idea? I have never used this on mains voltage devices.

WD40 = Bad idea. Save it for the rusty gate hinges.

Ron(UK)

Seán O'Leathlóbhair wrote:

I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds.

In order to do that it must be getting power from somewhere. You must have a
fault in the switch or related wiring.

Graham

Seán O'Leathlóbhair wrote:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

That would appear to be the case.

Graham

Eeyore writes:

Seán O'Leathlóbhair wrote:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

That would appear to be the case.

This is at least partly true.

Low energy lamps including compact fluorescents and normal fluorescents
on electronic ballasts use a switching circuit to produce the high voltage for
the fluorescent lamp. The input is a bridge rectifier and filter capacitor.
Any source of AC even a small amount of leakage through a defective swtich,
a switch with a neon lamp night light feature (lighted when off), an
electronic timer, a motion sensor-controlled yard light, or
a dimmer that isn't fully off, may cause the voltage to build up
on the filter capacitor until the "startup circuit" kicks in. This usually
has some sort of threshold de
vice like a zener diode or diac that won't
pass current until the voltage across it exceeds a spec'd value. When
that happens, the lamp starts up and strikes but just for an instant since
there isn't enough current available on the input to maintain it.

I'm somewhat skeptical of the explanation with respect to inductive or
capacitive coupling (though possible under just the right - or wrong -
conditions) but it doesn't take that much leakage from some other fault
to do this.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
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| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
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Sam Goldwasser wrote:
Eeyore writes:

Seán O'Leathlóbhair wrote:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.
That would appear to be the case.

This is at least partly true.

Low energy lamps including compact fluorescents and normal fluorescents
on electronic ballasts use a switching circuit to produce the high voltage for
the fluorescent lamp. The input is a bridge rectifier and filter capacitor.
Any source of AC even a small amount of leakage through a defective swtich,
a switch with a neon lamp night light feature (lighted when off), an
electronic timer, a motion sensor-controlled yard light, or
a dimmer that isn't fully off, may cause the voltage to build up
on the filter capacitor until the "startup circuit" kicks in. This usually
has some sort of threshold de
vice like a zener diode or diac that won't
pass current until the voltage across it exceeds a spec'd value. When
that happens, the lamp starts up and strikes but just for an instant since
there isn't enough current available on the input to maintain it.

I'm somewhat skeptical of the explanation with respect to inductive or
capacitive coupling (though possible under just the right - or wrong -
conditions) but it doesn't take that much leakage from some other fault
to do this.

Perhaps we've finally discovered perpetual motion

Take care.

Ken

On 26 Jun, 01:35, Ken Weitzel wrote:
Sam Goldwasser wrote:
Eeyore writes:

Seán O'Leathlóbhair wrote:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.
That would appear to be the case.

This is at least partly true.

Low energy lamps including compact fluorescents and normal fluorescents
on electronic ballasts use a switching circuit to produce the high voltage for
the fluorescent lamp. The input is a bridge rectifier and filter capacitor.
Any source of AC even a small amount of leakage through a defective swtich,
a switch with a neon lamp night light feature (lighted when off), an
electronic timer, a motion sensor-controlled yard light, or
a dimmer that isn't fully off, may cause the voltage to build up
on the filter capacitor until the "startup circuit" kicks in. This usually
has some sort of threshold de
vice like a zener diode or diac that won't
pass current until the voltage across it exceeds a spec'd value. When
that happens, the lamp starts up and strikes but just for an instant since
there isn't enough current available on the input to maintain it.

I'm somewhat skeptical of the explanation with respect to inductive or
capacitive coupling (though possible under just the right - or wrong -
conditions) but it doesn't take that much leakage from some other fault
to do this.

Perhaps we've finally discovered perpetual motion

Take care.


Well this light may be free in the sense it is being powered by energy
that was previously leaking unnoticed but I doubt that is free in the
sense that no energy is being consumed. The waste may even have been
reduced, the incandescent bulb may have drawn more from the leakage.

--
Seán Ó Leathlóbhair

In article , Sam Goldwasser
writes

I'm somewhat skeptical of the explanation with respect to inductive or
capacitive coupling (though possible under just the right - or wrong -
conditions)

In the UK, it's common to drill holes in floor joists and run several
circuits through them, including lighting (6A) and ring (32A) circuits.
Thus a long length of ring main cable running alongside the lighting
circuit in question would easily be sufficient to induce some current
flow in the lighting circuit. This is where the energy comes from to
cause the CFL to charge up and flash.

To the OP: it's entirely normal and not indicative of a fault at all.
You only need to do something if the flashing bothers you.

--
(\__/) Bunny says NO to Windows Vista!
(='.'=) http://www.cs.auckland.ac.nz/~pgut00...ista_cost.html
(")_(")

Mike Tomlinson wrote:

Sam Goldwasser writes

I'm somewhat skeptical of the explanation with respect to inductive or
capacitive coupling (though possible under just the right - or wrong -
conditions)

In the UK, it's common to drill holes in floor joists and run several
circuits through them, including lighting (6A) and ring (32A) circuits.
Thus a long length of ring main cable running alongside the lighting
circuit in question would easily be sufficient to induce some current
flow in the lighting circuit.

Not mA worth though.

Graham

Seán O'Leathlóbhair wrote:
I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

So many replies that it is hard to know which one to reply to so I
will reply here.

A curious feature that I forgot to mention is the regularlity of the
flashes: every 2 seconds with no variation that I can detect with a
stop watch. This is why I thought of a capacitor charging up until it
reaches a critical voltage. But I was thinking of DC. AC is not going
to charge up a capacitor over 2 seconds. What is inside these bulbs? A
rectifier? A capacitor?

I will do some checking at the weekend. Climb into the loft space for
a look. Get the multimeter out. Trying other low energy bulbs. Try the
higher rated bulb. Etc.

--
Seán Ó Leathlóbhair

Seán O'Leathlóbhair wrote:

What is inside these bulbs? A
rectifier? A capacitor?

Lots of stuff.

Graham

Hi!

I have a few questions:

What is going on?

See my other reply. Do you have a light switch that glows when you turn it
off? This will place a small amount of current flow across the lamp, which
may make it flicker.

Will it wear out the bulb very fast?

It may result in a slight amount of wear on the bulb, but I doubt the change
in lifetime would ever be noticed.

What is inside these bulbs? A rectifier? A capacitor?

In many cases, these bulbs contain a small switchmode power supply. Such a
power supply will have a transistor, some type of controller, a small
transformer and some support components (of which a capacitor would probably
be included). Others use a much simpler transformer design.

William

"William R. Walsh" m writes:

Hi!

I have a few questions:

What is going on?

See my other reply. Do you have a light switch that glows when you turn it
off? This will place a small amount of current flow across the lamp, which
may make it flicker.

Will it wear out the bulb very fast?

It may result in a slight amount of wear on the bulb, but I doubt the change
in lifetime would ever be noticed.

This I wouldn't be so sure of. Startup is hard on fluorescent lamps.

What is inside these bulbs? A rectifier? A capacitor?

In many cases, these bulbs contain a small switchmode power supply. Such a
power supply will have a transistor, some type of controller, a small
transformer and some support components (of which a capacitor would probably
be included). Others use a much simpler transformer design.

The transformer design will not experience this phenomenon.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
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On 25 Jun 2007 20:29:58 -0400, Sam Goldwasser
put finger to keyboard and composed:

"William R. Walsh" m writes:

Hi!

I have a few questions:

What is going on?

See my other reply. Do you have a light switch that glows when you turn it
off? This will place a small amount of current flow across the lamp, which
may make it flicker.

Will it wear out the bulb very fast?

It may result in a slight amount of wear on the bulb, but I doubt the change
in lifetime would ever be noticed.

This I wouldn't be so sure of. Startup is hard on fluorescent lamps.

I recently had two lamps (EDAPT 20W) fail in a relatively short time.
Curiosity got the better of me so I cracked them open to have a look.

Lamp A lasted about 3 months, lamp B about one week. Lamp A had an
open filament, and both had open "startup" resistors. Lamp B would
start when it was cold (or completely discharged?) but would not
restart just after it had been switched off. Lamp A would flash
briefly if I tapped it, despite the resistor being open. I'm wondering
whether the failure in the resistor caused the premature burnout of
the filament? If so, then this would be in line with your comment re
startup "trauma".

BTW, I repaired lamp B and it has been working ever since. I should
also mention that lamp A was full of dry solder joints which may have
contributed to its early demise.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

=?iso-8859-1?B?U2XhbiBPJ0xlYXRobPNiaGFpcg==?= writes:

Se=E1n O'Leathl=F3bhair wrote:
I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

So many replies that it is hard to know which one to reply to so I
will reply here.

A curious feature that I forgot to mention is the regularlity of the
flashes: every 2 seconds with no variation that I can detect with a
stop watch. This is why I thought of a capacitor charging up until it
reaches a critical voltage. But I was thinking of DC. AC is not going
to charge up a capacitor over 2 seconds. What is inside these bulbs? A
rectifier? A capacitor?

No, you're correct. See my (and other) replies. It is a capacitor
charging up - after a rectifier.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

I will do some checking at the weekend. Climb into the loft space for
a look. Get the multimeter out. Trying other low energy bulbs. Try the
higher rated bulb. Etc.

Seán O'Leathlóbhair wrote:

I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Seán Ó Leathlóbhair

This has come up before in aus.electronics though I don't recall if there
was a definite cure for it.

Chris

Chris Jones wrote:
Seán O'Leathlóbhair wrote:

I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Seán Ó Leathlóbhair

This has come up before in aus.electronics though I don't recall if there
was a definite cure for it.

Thanks. If there is no danger, I don't need a cure. The flash is not
irritating. The CO detector nearby flashes more brightly. I am just
worried that it is telling me that something nasty is wrong with my
wiring.

--
Seán Ó Leathlóbhair

"Seán O'Leathlóbhair" wrote in message
ups.com...
Chris Jones wrote:
Seán O'Leathlóbhair wrote:

I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Seán Ó Leathlóbhair

This has come up before in aus.electronics though I don't recall if there
was a definite cure for it.

Thanks. If there is no danger, I don't need a cure. The flash is not
irritating. The CO detector nearby flashes more brightly. I am just
worried that it is telling me that something nasty is wrong with my
wiring.

--
Seán Ó Leathlóbhair



It'll probably cause the CFL to fail much sooner than it otherwise would.
I'd check the wiring and switches just because it's easy to do, make sure
there isn't any moist gunk between contacts or anything else like that.
Another option is to wire a small incandescent bulb such as a nightlight in
parallel but this is not always practical.

Hi!

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds.

Do you have one of those switches that glows when you turn it off?

I have one attached to set a of conventional fluorescent fixtures (one four
tube and one two tube). When the switch is "off" it still passes a tiny
amount of current and this makes for a faint flashing in the two tube
fixture. As far as I can tell this is perfectly safe...it has never caused
any problems for the lamp or myself.

I do, however, have to turn the power off when changing the lamps in the two
tube fixture. Otherwise there is the possibility of getting a small shock.

William

William R. Walsh wrote:
Hi!

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds.

Do you have one of those switches that glows when you turn it off?

No, plain simple switches with no good reason to pass any current when
off.

I have one attached to set a of conventional fluorescent fixtures (one four
tube and one two tube). When the switch is "off" it still passes a tiny
amount of current and this makes for a faint flashing in the two tube
fixture. As far as I can tell this is perfectly safe...it has never caused
any problems for the lamp or myself.

I do, however, have to turn the power off when changing the lamps in the two
tube fixture. Otherwise there is the possibility of getting a small shock.

I noticed the problem when putting the bulb in - it blinked. Of
course, my first reaction was that I had left the switch on but this
was not a likely mistake since the previous incandescent bulb was not
dead.

--
Seán O'Leathlóbhair

Seán O'Leathlóbhair wrote:

I noticed the problem when putting the bulb in - it blinked.

There's something very odd going on if it did that.

Have you got a DVM/DMM ?

Graham

On Mon, 25 Jun 2007 07:03:01 -0700, Seán O'Leathlóbhair
put finger to keyboard and composed:

I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

There was a similar thread at aus.electronics earlier this year.

CFL "pulses" when off!
http://groups.google.com/group/aus.e...04b7d5a?hl=en&

I don't know if anything was resolved, but the distributor of a
certain CFL brand wrote:

"We have found after much research that certain homes that are wired
in a way where they are switching the neutral that this may occur with
these lamps."

One contributor theorised that the switch wire may act as a
capacitance. This would allow the main filter capacitor to gradually
charge up via the bridge rectifier to the point where the circuit may
"kick", after which the flash would discharge the capacitor and the
cycle would start again.

This person experimented with various series caps and resistors:
http://groups.google.com/group/aus.e...5398c8c?hl=en&

Here is an interesting site that shows what is inside these lamps:
http://www.pavouk.org/hw/lamp/en_index.html

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.


Is one of the switches illuminated? Those will pass enough current to slowly
charge up the filter capacitor in the fluorescent bulb and cause it to
blink.

"James Sweet" wrote in message
news:A61gi.6303$oo5.5110@trndny09...
When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.


Is one of the switches illuminated? Those will pass enough current to
slowly charge up the filter capacitor in the fluorescent bulb and cause it
to blink.


If it's leakage from anywhere, a bog-standard electricians neon test
screwdriver should show that up. Or try wiring a mains rated neon indicator
straight across the lampholder without the lamp in place. If it glows, you
have leakage either across one of the switches, or between lives. Bear in
mind that with a two way circuit, there are two wires, one or other of which
is always live, running (normally) in a common cable sheath, between the two
switches. Also bear in mind that the poster said in his third reply that not
only is there a two way switch at either end of the landing, there is
actually a third switch at the half way point where a corridor joins the
main hallway. I'm not quite sure how you factor a third switch into a
'standard' two-way circuit, but it occurs to me that it might well be
'stealing' its live either from a second lighting circuit, or from some
considerable distance around the lighting circuit, from where the main live
for the circuit is taken. Either way, that third switch must join into the
actual landing light circuit, via some kind of junction box, which may be
part of the light fixture ceiling rose, if that's nearby, or a separate
entity in the loft. It could be potentially another place for some kind of
leakage taking place.

Did anyone see in the Sunday paper, an article regarding these CFLs causing
pre-fit symptoms to epilepsy sufferers ? Seems it's becoming common, and the
same people don't suffer with ordinary flourescents. Some research suggests
that it might be to do with the (apparently) very uneven spectral response
of the tri-phosphors used to try to get an 'incandescent' colour. Hmmm ...

Arfa

On 26 Jun, 10:13, "Arfa Daily" wrote:
"James Sweet" wrote in message

news:A61gi.6303$oo5.5110@trndny09... When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

Is one of the switches illuminated? Those will pass enough current to
slowly charge up the filter capacitor in the fluorescent bulb and cause it
to blink.

If it's leakage from anywhere, a bog-standard electricians neon test
screwdriver should show that up. Or try wiring a mains rated neon indicator
straight across the lampholder without the lamp in place. If it glows, you
have leakage either across one of the switches, or between lives. Bear in
mind that with a two way circuit, there are two wires, one or other of which
is always live, running (normally) in a common cable sheath, between the two
switches. Also bear in mind that the poster said in his third reply that not
only is there a two way switch at either end of the landing, there is
actually a third switch at the half way point where a corridor joins the
main hallway. I'm not quite sure how you factor a third switch into a
'standard' two-way circuit, but it occurs to me that it might well be
'stealing' its live either from a second lighting circuit, or from some
considerable distance around the lighting circuit, from where the main live
for the circuit is taken. Either way, that third switch must join into the
actual landing light circuit, via some kind of junction box, which may be
part of the light fixture ceiling rose, if that's nearby, or a separate
entity in the loft. It could be potentially another place for some kind of
leakage taking place.

I do have a mains rated neon screwdriver so that will be one of my
first tests.

The third switch puzzled me when I moved to the house. I researched
how it could be done and I have posted a description elsewhere in the
thread. The system is rare in the UK but I read that it is common in
Spain and some other places. I have not yet checked whether my house
is wired as described but flicking any switch at any time will change
the state of the light so the switches are not simply in series or
parallel. If the wiring is as expected, there will be two alternative
live wires (always one live and one dead) running together for a
considerable distance, rather more than the length of the landing . A
leak between these two would explain the problem but not cause a fuse
to blow or an RCCB to trip.

Did anyone see in the Sunday paper, an article regarding these CFLs causing
pre-fit symptoms to epilepsy sufferers ? Seems it's becoming common, and the
same people don't suffer with ordinary flourescents. Some research suggests
that it might be to do with the (apparently) very uneven spectral response
of the tri-phosphors used to try to get an 'incandescent' colour. Hmmm ...


--
Seán Ó Leathlóbhair

On Jun 25, 8:03 am, Seán O'Leathlóbhair wrote:
I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Seán Ó Leathlóbhair

You have a more complicated circuit than you think. If you have 3
switches, each capable of turning the lamp on and off irrespective of
the positions of the other two switches, then the switches are not
directly connected to the lamp. The switches are connected to a (-n
electromechanical) relay or a solid-state relay. The relay provides
power to the lamp...the switches control the relay. I suspect leakage
somewhere in wiring between the switch(s) and the relay...which, if
solid-state, may require only a few milliamps to trip the relay.
Could also be that the control relay is defective somehow...

On Jun 26, 10:25 pm, webpa wrote:
On Jun 25, 8:03 am, Seán O'Leathlóbhair wrote:





I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Seán Ó Leathlóbhair

You have a more complicated circuit than you think. If you have 3
switches, each capable of turning the lamp on and off irrespective of
the positions of the other two switches, then the switches are not
directly connected to the lamp. The switches are connected to a (-n
electromechanical) relay or a solid-state relay. The relay provides
power to the lamp...the switches control the relay. I suspect leakage
somewhere in wiring between the switch(s) and the relay...which, if
solid-state, may require only a few milliamps to trip the relay.
Could also be that the control relay is defective somehow.

More complicated than the common two switch set-up but not necessarily
that complicated. I have not traced the wiring to be sure how this
particular installation works but I am reasonably sure that it does
not involve a relay. I have researched how it may work and I have
described that elsewhere in the thread. The switches need to be more
complicated than typical. They need two inputs and two outputs. Each
input is always connected to one of the outputs but the connections
are reversed when the switch is changed. The live goes to one input
of the first switch. The two outputs of the first switch are
connected to the two inputs of the second. This continues through as
many switches as you wish. Finally one output of the last switch is
connected to the bulb. The neutral is connected normally. So, if any
switch is changed, the live will go down the other wire through the
rest of the system. Since only one output of the last switch is
connected to the bulb, if it was on, it goes off but of it was off it
goes on. This set-up is rare in the UK but the necessary switches are
available, I have seen them in my local hardware shop. They can be
used for the more typical two switch set-up by simply ignoring one of
the terminals. I have read that this set-up is more commonly used in
some other countries such as Spain.

--
Seán Ó Leathlóbhair

"Seán O'Leathlóbhair" wrote in message
oups.com...
On Jun 26, 10:25 pm, webpa wrote:
On Jun 25, 8:03 am, Seán O'Leathlóbhair wrote:





I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Seán Ó Leathlóbhair

You have a more complicated circuit than you think. If you have 3
switches, each capable of turning the lamp on and off irrespective of
the positions of the other two switches, then the switches are not
directly connected to the lamp. The switches are connected to a (-n
electromechanical) relay or a solid-state relay. The relay provides
power to the lamp...the switches control the relay. I suspect leakage
somewhere in wiring between the switch(s) and the relay...which, if
solid-state, may require only a few milliamps to trip the relay.
Could also be that the control relay is defective somehow.

More complicated than the common two switch set-up but not necessarily
that complicated. I have not traced the wiring to be sure how this
particular installation works but I am reasonably sure that it does
not involve a relay. I have researched how it may work and I have
described that elsewhere in the thread. The switches need to be more
complicated than typical. They need two inputs and two outputs. Each
input is always connected to one of the outputs but the connections
are reversed when the switch is changed. The live goes to one input
of the first switch. The two outputs of the first switch are
connected to the two inputs of the second. This continues through as
many switches as you wish. Finally one output of the last switch is
connected to the bulb. The neutral is connected normally. So, if any
switch is changed, the live will go down the other wire through the
rest of the system. Since only one output of the last switch is
connected to the bulb, if it was on, it goes off but of it was off it
goes on. This set-up is rare in the UK but the necessary switches are
available, I have seen them in my local hardware shop. They can be
used for the more typical two switch set-up by simply ignoring one of
the terminals. I have read that this set-up is more commonly used in
some other countries such as Spain.

--
Seán Ó Leathlóbhair


And here is the way it's done - no magic, no relays or electronic control
circuits - just switches and wire ...

http://www.electrical-online.com/4waydiagram.htm

or

http://www.wfu.edu/~matthews/courses...itchesTut.html

Arfa

webpa writes:

On Jun 25, 8:03 am, Se=E1n O'Leathl=F3bhair wrote:
I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.

I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.

When it is switched on, it works as expected.

When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

I have a few questions:

What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.

Is it safe?

Will it wear out the bulb very fast?

Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).

Might I have to replace the wiring? (Much harder than just replacing
the switches)

--
Se=E1n =D3 Leathl=F3bhair

You have a more complicated circuit than you think. If you have 3
switches, each capable of turning the lamp on and off irrespective of
the positions of the other two switches, then the switches are not
directly connected to the lamp. The switches are connected to a (-n
electromechanical) relay or a solid-state relay. The relay provides
power to the lamp...the switches control the relay. I suspect leakage
somewhere in wiring between the switch(s) and the relay...which, if
solid-state, may require only a few milliamps to trip the relay.
Could also be that the control relay is defective somehow...

No, they only need be mechanical switches.

Google "3-way switch" and "4-way switch".

Or see the info at:

http://www.repairfaq.org/sam/appfaq.htm#afconfofm

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