LED Series Christmas Lights

[Tom Del Rosso]

Jeff Liebermann wrote:

I do like Christmas lights, but they only last until the squirrels are
done chewing on the wires.

In NYC in the 70's squirrels were very rare in the winter, but the lights
lasted a day or two, until the neighbors had stolen half the bulbs.


--

Reply in group, but if emailing add one more
zero, and remove the last word.

 

[Windmill]

klem kedidelhopper <captainvideo462009@gmail.com> writes:

On Dec 28, 5:49=A0am, "William Sommerwerck" <grizzledgee...@comcast.net
wrote:
"Jeff Liebermann" <je...@cruzio.com> wrote in message

news:ku3lf7tm101k0niv2q6oiojgo71dqtp0p0@4ax.com...

I do like Christmas lights, but they only last until the squirrels
are done chewing on the wires.

"Done", as in "thoroughly cooked"?

It would break your mother's heart if she knew you liked Christmas lights=
.

When I was 13 I reasoned that if you got a whole bunch of extension
cords and plugged them into various different outlets in the house,
then wired them all in series you could achieve infinite
possibilities. That was only topped by the 120.0 V to 6.0 volt step
down transformer I tried to wind on the metal frame of my bed. The
schematic showed 8 turns on the primary and 2 on the secondary.
Couldn't figure out why I lit up he room.....Lenny

It's astonishing that we survived until we were able to misunderstand
on a more sophisticated level.

Not as long ago as I would like it to be, I reasoned that since the
magnetron in a 1 megawatt (peak) early-warning radar presented an
impedance of about 500 ohms to the driving circuitry, a 1 kilowatt
microwave oven would use voltages of about 700 volts.
The meter I'd borrowed from a friend to look at his microwave sparked
internally (he claimed there was a blue glow, but he'd seen too many
mad scientist movies).

I now know better, having better access to information!

--
Windmill, TiltNot@Nonetel.com Use t m i l l
J.R.R. Tolkien:- @ O n e t e l . c o m
All that is gold does not glister / Not all who wander are lost

 

[Windmill]

Jeff Liebermann <jeffl@cruzio.com> writes:

These days, repair work has changed. In the bad old days, it was
assumed that most items worth repairing were of decent quality. These
days, I can't just repair things. I have to re-engineer the design
and try to improve on what I consider to be crappy design and shoddy
construction. In the past, products were usually designed to be
maintained. These days, they're designed to be non-repairable.

Or at least that's what they specifically claim, in some cases.

When my electric toothbrush's battery refused to hold a charge, I
looked at the insane price of replacements and took the old one apart.

It had an O ring which sealed against water ingress, so reusable with
some cleaning, and had a tabbed AA size NiCd which showed normal
voltage until loaded by the motor so obviously dead.

The battery turned out to be suspiciously light. Probably the deluxe
model had a normal AA while my economy model was really a 1/3 AA
internally.

Tinning an NiMH replacement to allow soldering on the tags turned out
to be far easier than I expected; I shouldn't have dabbed on zinc chloride
flux with a cotton swab because this resulted in tinning of the whole
base, thus heating the battery unnecessarily.
A dab from the end of a cocktail stick would have been better (and yes,
I know it's corrosive but supposedly quick tinning is important to
avoid battery damage).

Actually, it's not repair as much as it is remanufacture.

Don't know how long the repair will last, and recharging may take a
long time, but the motor seems to have a bit more power and the first
charge has given many more days of use.

In some
product areas, it's impossible to buy quality at any price.

Or there's little correlation between quality and price.
The bean counters usually get the blame.

--
Windmill, TiltNot@Nonetel.com Use t m i l l
J.R.R. Tolkien:- @ O n e t e l . c o m
All that is gold does not glister / Not all who wander are lost

 

[klem kedidelhopper]

On Dec 30, 6:13 pm, "Tom Del Rosso" <td...@verizon.net.invalid> wrote:

Jeff Liebermann wrote:
I do like Christmas lights, but they only last until the squirrels are
done chewing on the wires.

In NYC in the 70's squirrels were very rare in the winter, but the lights
lasted a day or two, until the neighbors had stolen half the bulbs.

--

Reply in group, but if emailing add one more
zero, and remove the last word.

There are no squirrels in NYC. The roaches ate them all. Lenny

 

[hrhofmann@att.net]

On Dec 30, 10:04 pm, klem kedidelhopper <captainvideo462...@gmail.com>
wrote:

On Dec 30, 6:13 pm, "Tom Del Rosso" <td...@verizon.net.invalid> wrote:

Jeff Liebermann wrote:
I do like Christmas lights, but they only last until the squirrels are
done chewing on the wires.

In NYC in the 70's squirrels were very rare in the winter, but the lights
lasted a day or two, until the neighbors had stolen half the bulbs.

--

Reply in group, but if emailing add one more
zero, and remove the last word.

There are no squirrels in NYC. The roaches ate them all. Lenny

Naw, the rats eat the squirrels, the roaches eat the rats.

 

[Jeff Liebermann]

On Fri, 30 Dec 2011 18:13:02 -0500, "Tom Del Rosso"
<td_03@verizon.net.invalid> wrote:

Jeff Liebermann wrote:
I do like Christmas lights, but they only last until the squirrels are
done chewing on the wires.

In NYC in the 70's squirrels were very rare in the winter, but the lights
lasted a day or two, until the neighbors had stolen half the bulbs.

Yeah, but NY squirrels have their own blog:
<http://thenewyorksquirrel.blogspot.com>
See bottom of page for instructions on how to create a problem. The
problem I have with squirrels is:
1. They chew on Hannukah lights.
2. They chew on garden hoses.
3. They chew on my antenna cables.
4. They take one bite out of EVERY pear on my tree. They don't like
pears, but that doesn't stop them from trashing the entire crop.
5. They harass the cats.
6. They wake me up in the morning by banging acorns on my roof.

Bulbs? LED's are the high fashion decorations. No bulbs to unscrew.
Attach with a staple gun to discourage someone from stealing the
entire string. Extra credit for installing a current sensor on the AC
power outlet, and having an alarm sound if it sees a current drop,
caused by a bulb disappearing (or blowing up).

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[klem kedidelhopper]

On Dec 30, 11:45 pm, "hrhofm...@att.net" <hrhofm...@att.net> wrote:

On Dec 30, 10:04 pm, klem kedidelhopper <captainvideo462...@gmail.com
wrote:

On Dec 30, 6:13 pm, "Tom Del Rosso" <td...@verizon.net.invalid> wrote:

Jeff Liebermann wrote:
I do like Christmas lights, but they only last until the squirrels are
done chewing on the wires.

In NYC in the 70's squirrels were very rare in the winter, but the lights
lasted a day or two, until the neighbors had stolen half the bulbs.

--

Reply in group, but if emailing add one more
zero, and remove the last word.

There are no squirrels in NYC. The roaches ate them all. Lenny

Naw, the rats eat the squirrels, the roaches eat the rats.

Either way it's inevitable who wins in the end.....Lenny

 

[Michael A. Terrell]

Windmill wrote:

klem kedidelhopper <captainvideo462009@gmail.com> writes:

On Dec 28, 5:49=A0am, "William Sommerwerck" <grizzledgee...@comcast.net
wrote:
"Jeff Liebermann" <je...@cruzio.com> wrote in message

news:ku3lf7tm101k0niv2q6oiojgo71dqtp0p0@4ax.com...

I do like Christmas lights, but they only last until the squirrels
are done chewing on the wires.

"Done", as in "thoroughly cooked"?

It would break your mother's heart if she knew you liked Christmas lights=
.

When I was 13 I reasoned that if you got a whole bunch of extension
cords and plugged them into various different outlets in the house,
then wired them all in series you could achieve infinite
possibilities. That was only topped by the 120.0 V to 6.0 volt step
down transformer I tried to wind on the metal frame of my bed. The
schematic showed 8 turns on the primary and 2 on the secondary.
Couldn't figure out why I lit up he room.....Lenny

It's astonishing that we survived until we were able to misunderstand
on a more sophisticated level.

Not as long ago as I would like it to be, I reasoned that since the
magnetron in a 1 megawatt (peak) early-warning radar presented an
impedance of about 500 ohms to the driving circuitry, a 1 kilowatt
microwave oven would use voltages of about 700 volts.

Have you ever been near, or inside a high power RADAR system? We
had two at Ft Rucker in the '70s Each ran 2 MW to track aircraft around
the base, and to the Gulf of Mexico. One was always being serviced
while the other was in use, to reduce the chances of both being down.
Both transmitters, and the high intensity RF from the antenna could kill
in less than a heartbeat.

A 25 KW RCA TTU-25B TV transmitter I rebuilt used 7 KV on the plates.

The meter I'd borrowed from a friend to look at his microwave sparked
internally (he claimed there was a blue glow, but he'd seen too many
mad scientist movies).

You're lucky that you didn't kill yourself.

I now know better, having better access to information!

--
Windmill, TiltNot@Nonetel.com Use t m i l l
J.R.R. Tolkien:- @ O n e t e l . c o m
All that is gold does not glister / Not all who wander are lost

--
You can't have a sense of humor, if you have no sense.

 

[Michael A. Terrell]

klem kedidelhopper wrote:

On Dec 30, 6:13 pm, "Tom Del Rosso" <td...@verizon.net.invalid> wrote:
Jeff Liebermann wrote:
I do like Christmas lights, but they only last until the squirrels are
done chewing on the wires.

In NYC in the 70's squirrels were very rare in the winter, but the lights
lasted a day or two, until the neighbors had stolen half the bulbs.

There are no squirrels in NYC. The roaches ate them all. Lenny

Only the non-union roaches. The union roaches were on strike.


--
You can't have a sense of humor, if you have no sense.

 

[Roger Jones]

On Dec 28, 1:10 am, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

"hrhofm...@att.net" wrote:

On Dec 27, 12:54 am, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:
"hrhofm...@att.net" wrote:

I recently was given two strings of LED blue/white Christmas lights..
The bulbes are in series, with 35 lights in each string.  There are
also a couple of lumps in the series lines.  They appear to be just
resistors, not diodes, as I measure the same value (~500 ohms) with
either polarity of my multimeter.   My guess is that the resistors are
there just to decrease the current so that the LEDs are not running
overrrated.  I am thinking of putting/rewiring the two strings
directly in series and then reducing the series resistors until I get
the same overall brightness of the new 70-light string.  Has anyone
done any experimenting like this?

   Leave it alone. The forward voltage drop on white or blue LEDs is
higher than red or green, so that's why they chose  35 LEDs per string.
If you get too close to the actual line voltage and use lower
resistance, any spike will cause a high current surge through the
string.  If you aren't capable and willing to design and build a
constant current boost supply, you are wasting your time.

Good point about surge limiting, altho I am not sure if LEDs are any
more susceptible than tungsten filament lamps.

   Tungsten has a time constant, and the resistance goes up as the
voltage increases.  LEDs are current operated at a lot more constant
voltage.  A few volt rise in the power line rasies the current flow.
Harmonics and spikes on the power line will cause higher peak current
flow in the LEDs. It would be like operating a Zener very close to it's
knee voltage with only a very low resistance to limit the current.

--
You can't have a sense of humor, if you have no sense.

.... and LED's are very intolerant of PIV voltage. Any AC use requires
diodes to block or shunt the other 1/2 cycle. I prefer the shunt
method as it does not require the protection diode to have an infinite
reverse resistance.
Cheers,
Roger

 

[Windmill]

"Michael A. Terrell" <mike.terrell@earthlink.net> writes:

Have you ever been near, or inside a high power RADAR system? We
had two at Ft Rucker in the '70s Each ran 2 MW to track aircraft around
the base, and to the Gulf of Mexico. One was always being serviced
while the other was in use, to reduce the chances of both being down.
Both transmitters, and the high intensity RF from the antenna could kill
in less than a heartbeat.

Urban legend had it that someone had found a way, in the days before
vasectomies, to stand in front of a radar antenna for just long enough
to produce temporary sterilization.
But I didn't try that; doubtful if anyone would.

A 25 KW RCA TTU-25B TV transmitter I rebuilt used 7 KV on the plates.

My faulty assumption was that CW magnetrons used in microwaves had
similar characteristics (except for scale) to the pulsed
magnetrons used for radar. So I expected only 700 volts into 500 ohms.

The meter I'd borrowed from a friend to look at his microwave sparked
internally (he claimed there was a blue glow, but he'd seen too many
mad scientist movies).

You're lucky that you didn't kill yourself.

Not really. I hooked up the meter then stood well back before turning
on the microwave. (Wasn't really all that sure about the voltage
levels).

I now know better, having better access to information!
--

Windmill, TiltNot@Nonetel.com Use t m i l l
J.R.R. Tolkien:- @ O n e t e l . c o m
All that is gold does not glister / Not all who wander are lost

 

[William Sommerwerck]

"Windmill" <spam-no-spam@Onetel.net.uk.invalid> wrote in message
news:Lx5IBv.MBy@freebie.onetel.net.uk...

"Michael A. Terrell" <mike.terrell@earthlink.net> writes:

Have you ever been near, or inside a high power RADAR system? We
had two at Ft Rucker in the '70s Each ran 2 MW to track aircraft around
the base, and to the Gulf of Mexico. One was always being serviced
while the other was in use, to reduce the chances of both being down.
Both transmitters, and the high intensity RF from the antenna could kill
in less than a heartbeat.

Unless you were standing near a tightly focused beam, this is unlikely.
Microwaves kill by overheating, and the first thing heated would be the
outer surface of your body, which probably wouldn't be lethal. It's more
likely you'd be blinded by having your corneas cooked.

Urban legend had it that someone had found a way, in the days before
vasectomies, to stand in front of a radar antenna for just long enough
to produce temporary sterilization. But I didn't try that; doubtful if
anyone
would.

You could just as well dip your testicles in a bowl of hot water for 15
minutes.

 

[Michael A. Terrell]

William Sommerwerck wrote:

"Windmill" <spam-no-spam@Onetel.net.uk.invalid> wrote in message
news:Lx5IBv.MBy@freebie.onetel.net.uk...
"Michael A. Terrell" <mike.terrell@earthlink.net> writes:

Have you ever been near, or inside a high power RADAR system? We
had two at Ft Rucker in the '70s Each ran 2 MW to track aircraft around
the base, and to the Gulf of Mexico. One was always being serviced
while the other was in use, to reduce the chances of both being down.
Both transmitters, and the high intensity RF from the antenna could kill
in less than a heartbeat.

Unless you were standing near a tightly focused beam, this is unlikely.
Microwaves kill by overheating, and the first thing heated would be the
outer surface of your body, which probably wouldn't be lethal. It's more
likely you'd be blinded by having your corneas cooked.

Birds would drop dead if they flew too close to that RADAR antenna,
but the highest risk of death was from the high current, high voltage
power supplies in tube type microwave sources. High power RADAR tubes
were huge, when compared to the lowly Magnetron in an oven.

Urban legend had it that someone had found a way, in the days before
vasectomies, to stand in front of a radar antenna for just long enough
to produce temporary sterilization. But I didn't try that; doubtful if
anyone
would.

You could just as well dip your testicles in a bowl of hot water for 15
minutes.

That is used when Water boarding fails. ;-)


--
You can't have a sense of humor, if you have no sense.

 

[Windmill]

"Michael A. Terrell" <mike.terrell@earthlink.net> writes:

William Sommerwerck wrote:

"Windmill" <spam-no-spam@Onetel.net.uk.invalid> wrote in message
news:Lx5IBv.MBy@freebie.onetel.net.uk...
"Michael A. Terrell" <mike.terrell@earthlink.net> writes:

Have you ever been near, or inside a high power RADAR system? We
had two at Ft Rucker in the '70s Each ran 2 MW to track aircraft around
the base, and to the Gulf of Mexico. One was always being serviced
while the other was in use, to reduce the chances of both being down.
Both transmitters, and the high intensity RF from the antenna could kill
in less than a heartbeat.

Unless you were standing near a tightly focused beam, this is unlikely.
Microwaves kill by overheating, and the first thing heated would be the
outer surface of your body, which probably wouldn't be lethal. It's more
likely you'd be blinded by having your corneas cooked.

Birds would drop dead if they flew too close to that RADAR antenna,
but the highest risk of death was from the high current, high voltage
power supplies in tube type microwave sources. High power RADAR tubes
were huge, when compared to the lowly Magnetron in an oven.

I think you must be talking about much newer equipment than I worked
on.
Long ago, magnetrons (of a different design from the ones still used in
microwave ovens) were the only way to generate high peak powers, and
the oscillation frequency of a magnetron wasn't very stable.

Since then, I hear that high power klystrons have been used as
amplifiers in radar systems, and I believe there's a still newer tube
type which is used in the latest gear.

But as you say, the power supplies are and were very dangerous, needing
elaborate interlock systems to enhance safety.

Urban legend had it that someone had found a way, in the days before
vasectomies, to stand in front of a radar antenna for just long enough
to produce temporary sterilization. But I didn't try that; doubtful if
anyone
would.

You could just as well dip your testicles in a bowl of hot water for 15
minutes.

That is used when Water boarding fails. ;-)

The radar tale was probably meant as a warning which would have a
considerable effect on most young guys!

--
Windmill, TiltNot@Nonetel.com Use t m i l l
J.R.R. Tolkien:- @ O n e t e l . c o m
All that is gold does not glister / Not all who wander are lost

 

[Michael A. Terrell]

Windmill wrote:

"Michael A. Terrell" <mike.terrell@earthlink.net> writes:

Birds would drop dead if they flew too close to that RADAR antenna,
but the highest risk of death was from the high current, high voltage
power supplies in tube type microwave sources. High power RADAR tubes
were huge, when compared to the lowly Magnetron in an oven.

I think you must be talking about much newer equipment than I worked
on.

The system was a few yeas old in '72, when I arrived. I think those
systems were custom built by Westinghouse. I worked on so many custom
and semi custom items in the Army that I don't remember, almost 40 years
later. The oldest I repaired was made and deployed during the Korean
war. They were so called 'Portable' systems.

Long ago, magnetrons (of a different design from the ones still used in
microwave ovens) were the only way to generate high peak powers, and
the oscillation frequency of a magnetron wasn't very stable.

Not that they weren't stable. They were powered with unfilterd DC,
which caused a wideband output. They are operated as a self excited
oscllator when used in a microwave, and as long as the thisng is in
band, the frequency or bandwitch doesn't really matter. Have you ever
read the MIT Rad Lab series of declassified W.W.-II books, or Slotnik's
RADAR Handbook?

Since then, I hear that high power klystrons have been used as
amplifiers in radar systems, and I believe there's a still newer tube
type which is used in the latest gear.

I've worked with 65 KW EEV Klystrons. A Comark with three of them,
on TV Ch 55 were located in Orange City Florida. They had just ordered
the transmitter when Kystrodes were introduced. Today, the TV
transmitters are all solid state.

But as you say, the power supplies are and were very dangerous, needing
elaborate interlock systems to enhance safety.

Not just the power supplies. The gates to get to the RADAR antenna
had multiple key switches to disable the entire system

Urban legend had it that someone had found a way, in the days before
vasectomies, to stand in front of a radar antenna for just long enough
to produce temporary sterilization. But I didn't try that; doubtful if
anyone
would.

You could just as well dip your testicles in a bowl of hot water for 15
minutes.

That is used when Water boarding fails. ;-)

The radar tale was probably meant as a warning which would have a
considerable effect on most young guys!

I saw dead birds in the parking lot fairly often, for the nine months
I was s tationed at that RADAR site.

--
You can't have a sense of humor, if you have no sense.

 

[josephkk]

On Mon, 2 Jan 2012 23:36:55 GMT, spam-no-spam@Onetel.net.uk.invalid
(Windmill) wrote:

Birds would drop dead if they flew too close to that RADAR antenna,
but the highest risk of death was from the high current, high voltage
power supplies in tube type microwave sources. High power RADAR tubes
were huge, when compared to the lowly Magnetron in an oven.

I think you must be talking about much newer equipment than I worked
on.
Long ago, magnetrons (of a different design from the ones still used in
microwave ovens) were the only way to generate high peak powers, and
the oscillation frequency of a magnetron wasn't very stable.

Since then, I hear that high power klystrons have been used as
amplifiers in radar systems, and I believe there's a still newer tube
type which is used in the latest gear.

I believe you are talking about a thing called a gyrotron. Useful at 100
GHz to 300 GHz in different models and uses.

But as you say, the power supplies are and were very dangerous, needing
elaborate interlock systems to enhance safety.

 

[spamtrap1888]

On Jan 3, 6:05 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

Windmill wrote:
Long ago, magnetrons (of a different design from the ones still used in
microwave ovens) were the only way to generate high peak powers, and
the oscillation frequency of a magnetron wasn't very stable.

   Not that they weren't stable.  They were powered with unfilterd DC,
which caused a wideband output.  They are operated as a self excited
oscllator when used in a microwave, and as long as the thisng is in
band, the frequency or bandwitch doesn't really matter.  Have you ever
read the MIT Rad Lab series of declassified W.W.-II books, or Slotnik's
RADAR Handbook?

Isn't the frequency determined by the dimensions of the cavity the
energy is dumped into? Or does that tune it too broadly?

 

[Michael A. Terrell]

spamtrap1888 wrote:

On Jan 3, 6:05 pm, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:

Windmill wrote:
Long ago, magnetrons (of a different design from the ones still used in
microwave ovens) were the only way to generate high peak powers, and
the oscillation frequency of a magnetron wasn't very stable.

Not that they weren't stable. They were powered with unfilterd DC,
which caused a wideband output. They are operated as a self excited
oscllator when used in a microwave, and as long as the thisng is in
band, the frequency or bandwitch doesn't really matter. Have you ever
read the MIT Rad Lab series of declassified W.W.-II books, or Slotnik's
RADAR Handbook?

Isn't the frequency determined by the dimensions of the cavity the
energy is dumped into? Or does that tune it too broadly?

The dimensions are the largest part of determining the frequency, but
it can be 'pulled' by voltage. Since it isn't run in CW mode in a
microwave, the oscillation has to start each time the plate voltage is
high enough on the unfiltered DC supply. The magnetron is designed for
the application, to keep it operating in the assigned band in this mode
of operation.


--
You can't have a sense of humor, if you have no sense.

 

[William Sommerwerck]

Not that they weren't stable. They were powered with unfilterd DC,
which caused a wideband output. They are operated as a self excited
oscllator when used in a microwave, and as long as the thing is in
band, the frequency or bandwitch doesn't really matter.

Wasn't that an Eagles song? "Bandwitchy Woman"?

Isn't the frequency determined by the dimensions of the cavity
the energy is dumped into? Or does that tune it too broadly?

If I understand your misunderstanding... "Wideband" refers to the "spuriae"
generated by the unfiltered 60 Hz and its harmonics.

 

[Michael A. Terrell]

William Sommerwerck wrote:

Not that they weren't stable. They were powered with unfilterd DC,
which caused a wideband output. They are operated as a self excited
oscllator when used in a microwave, and as long as the thing is in
band, the frequency or bandwitch doesn't really matter.

Wasn't that an Eagles song? "Bandwitchy Woman"?

Isn't the frequency determined by the dimensions of the cavity
the energy is dumped into? Or does that tune it too broadly?

If I understand your misunderstanding... "Wideband" refers to the "spuriae"
generated by the unfiltered 60 Hz and its harmonics.

AKA 'Phase Noise'.


--
You can't have a sense of humor, if you have no sense.