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February 4, 2017, 12:49 pm

For months I have been having problems with tv reception TV not working
on most channels for hours, I have been blaming 4g towers, fixed
wireless towers etc that have just been put up etc.
I have just found the cause by accident, almost unbelievable.
TV does not work if the kitchen light is on.
The culprit is one of these, a 12" or so multiple led ceiling LED
similar to this,
http://imgur.com/a/dj5ha
on most channels for hours, I have been blaming 4g towers, fixed
wireless towers etc that have just been put up etc.
I have just found the cause by accident, almost unbelievable.
TV does not work if the kitchen light is on.
The culprit is one of these, a 12" or so multiple led ceiling LED
similar to this,
http://imgur.com/a/dj5ha

Re: Tv reception

Its been a possible problem with CFLs for years.
Some of the LED replacement bulbs use a wattless dropper instead of SMPSU
circuitry. You might be able to adapt it, but don't forget to include a
surge limiting resistor - the current is very high around the zero crossing
portion of the AC waveform.
All the LED bulbs I've pulled apart had SMD resistors, so I didn't bother
tracing the schematic - there was a very handy CFL blog, maybe LED bulbs
have caught up.

Re: Tv reception

Geez - and I thought I wasn't great at AC theory..........................
A coupling capacitor (wattless dropper) blocks DC, the AC waveform is almost
that at the peaks. The capacitor only passes a rate of change - that's at
its greatest around the zero crossing points.
Maybe you should lay off the booze (or whatever)........

Re: Tv reception
On 07-Feb-17 5:15 AM, Benderthe.evilrobot wrote:

I have put such a circuit in a simulator, and except for the inrush
current I don't see anything like you said.
Try it yourself, like on: http://www.falstad.com/circuit/
Select 'File', 'import from text', and paste this text, a simple example:
$ 1 0.000005 3.452441195350251 45 5 43
s 688 96 752 96 0 0 false
v 752 368 752 96 0 1 50 330 0 0 0.5
d 480 352 480 240 1 0.805904783
d 576 112 576 208 1 0.805904783
w 688 96 576 96 0
w 576 96 576 112 0
w 480 96 576 96 0
w 480 352 480 368 0
d 416 144 416 96 1 0.805904783
d 416 272 416 352 1 0.805904783
w 480 96 416 96 0
w 416 352 416 368 0
w 432 368 480 368 0
370 688 368 752 368 1 0
162 480 224 480 160 1 2.1024259 1 0 0 0.01
162 512 224 512 160 1 2.1024259 1 0 0 0.01
162 544 224 544 160 1 2.1024259 1 0 0 0.01
w 480 144 480 160 0
w 480 160 512 160 0
w 512 160 544 160 0
w 544 224 512 224 0
w 512 224 480 224 0
w 432 144 416 144 0
c 560 368 624 368 0 5e-7 -9.1361757825205
w 688 368 624 368 0
w 560 368 480 368 0
w 416 144 416 160 0
w 416 160 416 272 0
w 432 368 416 368 0
w 432 144 480 144 0
w 480 240 480 224 0
r 560 320 624 320 0 220000
w 560 320 560 368 0
w 624 320 624 368 0
w 576 208 576 224 0
w 480 240 576 240 0
w 576 240 576 224 0
o 1 64 0 2083 640 0.1 0 -1 0
o 30 64 0 2083 640 0.1 1 -1 0
You have to reset the simulation and start again do get the current
range to normal after the inrush.
AFAIK The only important thing to remember is to use at least an X3
rated capacitor and a discharge resistor across the cap, so yo don't get
zapped when touching the open pins.

I have put such a circuit in a simulator, and except for the inrush
current I don't see anything like you said.
Try it yourself, like on: http://www.falstad.com/circuit/
Select 'File', 'import from text', and paste this text, a simple example:
$ 1 0.000005 3.452441195350251 45 5 43
s 688 96 752 96 0 0 false
v 752 368 752 96 0 1 50 330 0 0 0.5
d 480 352 480 240 1 0.805904783
d 576 112 576 208 1 0.805904783
w 688 96 576 96 0
w 576 96 576 112 0
w 480 96 576 96 0
w 480 352 480 368 0
d 416 144 416 96 1 0.805904783
d 416 272 416 352 1 0.805904783
w 480 96 416 96 0
w 416 352 416 368 0
w 432 368 480 368 0
370 688 368 752 368 1 0
162 480 224 480 160 1 2.1024259 1 0 0 0.01
162 512 224 512 160 1 2.1024259 1 0 0 0.01
162 544 224 544 160 1 2.1024259 1 0 0 0.01
w 480 144 480 160 0
w 480 160 512 160 0
w 512 160 544 160 0
w 544 224 512 224 0
w 512 224 480 224 0
w 432 144 416 144 0
c 560 368 624 368 0 5e-7 -9.1361757825205
w 688 368 624 368 0
w 560 368 480 368 0
w 416 144 416 160 0
w 416 160 416 272 0
w 432 368 416 368 0
w 432 144 480 144 0
w 480 240 480 224 0
r 560 320 624 320 0 220000
w 560 320 560 368 0
w 624 320 624 368 0
w 576 208 576 224 0
w 480 240 576 240 0
w 576 240 576 224 0
o 1 64 0 2083 640 0.1 0 -1 0
o 30 64 0 2083 640 0.1 1 -1 0
You have to reset the simulation and start again do get the current
range to normal after the inrush.
AFAIK The only important thing to remember is to use at least an X3
rated capacitor and a discharge resistor across the cap, so yo don't get
zapped when touching the open pins.

Re: Tv reception
On 08-Feb-17 3:42 AM, Benderthe.evilrobot wrote:

No, you have to reset it because the range of the current display has
expanded so much, by the inrush, that you don't see the normal current
curve. There is no such thing as a current peak once it is on. There is
a switch on the top right of the schematics. You can click on it to
switch on and off and see what the circuit does, as well.
I have built and used such circuits often.
Using an X rated capacitor or/and a small "sacrificial" resistor in
series will make sure that it won't catch fire due to a short in the
capacitor.

No, you have to reset it because the range of the current display has
expanded so much, by the inrush, that you don't see the normal current
curve. There is no such thing as a current peak once it is on. There is
a switch on the top right of the schematics. You can click on it to
switch on and off and see what the circuit does, as well.
I have built and used such circuits often.
Using an X rated capacitor or/and a small "sacrificial" resistor in
series will make sure that it won't catch fire due to a short in the
capacitor.

Re: Tv reception

"normal current curve"? - its only the sinusoidal drive that takes the edge
off the capacitor current that peaks around the zero crossing point.
You could switch the circuit on *ANYWHERE* on the cycle - it could be at the
peak and cause a big current pulse, or at zero where it starts at zero and
rises pretty much the same as continuous operation.
The AC current in a theoretically ideal capacitor leads voltage by 90
degrees - its not some great mystery from an alternate universe with
different laws of physics.

Re: Tv reception
On 09-Feb-17 3:18 AM, Benderthe.evilrobot wrote:

It's you that need to get real. The current does not "get very high'
around the zero crossing. It just reaches its maximum there because of
the phase shift of the capacitor. The resistor you were talking about is
only there to protect the circuit from melt down in case the capacitor
shorts out. Full stop. Unless you have a non-linear load that's just the
end of the discussion.

It's you that need to get real. The current does not "get very high'
around the zero crossing. It just reaches its maximum there because of
the phase shift of the capacitor. The resistor you were talking about is
only there to protect the circuit from melt down in case the capacitor
shorts out. Full stop. Unless you have a non-linear load that's just the
end of the discussion.

Re: Tv reception
On Thu, 9 Feb 2017 21:51:41 -0000, "Benderthe.evilrobot"

Would like to know how old "F Murtz" aerial is?
Is it a old Analogue or new digital?
Live in almost same area and my old Analogue was causing loss of
reception when turning almost anything on.
Decided to remove Analogue get Terracotta Tile roof washed new
gutters and fascia.
Then paid $90 for TV guy to put in new digital aerial problem gone.

Would like to know how old "F Murtz" aerial is?
Is it a old Analogue or new digital?
Live in almost same area and my old Analogue was causing loss of
reception when turning almost anything on.
Decided to remove Analogue get Terracotta Tile roof washed new
gutters and fascia.
Then paid $90 for TV guy to put in new digital aerial problem gone.
--
Petzl
Arguing with a woman is like reading the Software License Agreement.
Petzl
Arguing with a woman is like reading the Software License Agreement.
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