looking for a picture of CRT EHT arcing

[colin]

Hi,
I was hoping to find a picture on google images that showed how
long a spark you can get from the final anode of a crt, ie 25kv

mainly to point how dangerous it potentially is,
particularly when trying to discharge it.

but i couldnt find much, lots of other interesting sparks
though, and some lopt based spark generators but doesnt show the
scale so wel ie. relative to the inside of the tv or monitor.

I just wondered if theres any photo experts have managed to
catch something like an eht flashover ?
or though i think those are mostly internal to the crt and unseen.

Colin.

 

[Boris Mohar]

Hi,
I was hoping to find a picture on google images that showed how
long a spark you can get from the final anode of a crt, ie 25kv

mainly to point how dangerous it potentially is,
particularly when trying to discharge it.

but i couldnt find much, lots of other interesting sparks
though, and some lopt based spark generators but doesnt show the
scale so wel ie. relative to the inside of the tv or monitor.

I just wondered if theres any photo experts have managed to
catch something like an eht flashover ?
or though i think those are mostly internal to the crt and unseen.

Colin.

http://images.google.ca/images?um=1...&hs=cPj&q=tv+flyback+spark&btnG=Search+Images


Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

void _-void-_ in the obvious place

 

[colin]

http://images.google.ca/images?um=1...&hs=cPj&q=tv+flyback+spark&btnG=Search+Images


Regards,

Boris Mohar

thanks i waded though lots more spark pictures

i went for this one in the end ...
http://tesladownunder.com/FlybackTV250W.jpg

doesnt show it actually in the TV as such
but quite spectacular, and clearly uses a lopt,
probably realistic of a high voltage monitor,
perhaps a bit tweaked though lol.
thanks
Colin

 

[Jan Panteltje]

Hi,
I was hoping to find a picture on google images that showed how
long a spark you can get from the final anode of a crt, ie 25kv

mainly to point how dangerous it potentially is,
particularly when trying to discharge it.

It is not that dangerous, been bitten by that 25kV many times.
It is only _dangerous_ when you take out the tube, and a spark hits
you from the still charged CRT, and you drop the tube as a reaction.
At one time I forgot to reconnect th HV connection, it was hanging of the workbench,
and sparked through my pants.
Makes you jump!

 

[Rich Grise]

I was hoping to find a picture on google images that showed how long a
spark you can get from the final anode of a crt, ie 25kv

mainly to point how dangerous it potentially is, particularly when trying
to discharge it.

but i couldnt find much, lots of other interesting sparks though, and some
lopt based spark generators but doesnt show the scale so wel ie. relative
to the inside of the tv or monitor.

I just wondered if theres any photo experts have managed to catch
something like an eht flashover ? or though i think those are mostly
internal to the crt and unseen.

Not really apropos, but kinda kewl - in HS physics, they had a little lab
with an old TV and a scope and meters and stuff. One day, I thought it'd
be cool to scope out the waveform at the hor. driver anode, and it made
an arc about 2" long from the anode cap to the scope probe.

I didn't get any pictures - I had assumed it was only going to be a couple
of hundred volts - I had not learned about "flyback" yet.

Cheers!
Rich

 

[JosephKK]

Not really apropos, but kinda kewl - in HS physics, they had a little lab
with an old TV and a scope and meters and stuff. One day, I thought it'd
be cool to scope out the waveform at the hor. driver anode, and it made
an arc about 2" long from the anode cap to the scope probe.

I didn't get any pictures - I had assumed it was only going to be a couple
of hundred volts - I had not learned about "flyback" yet.

Cheers!
Rich

In most old tube sets i serviced (i was still a kid) the H. Output
anode stayed under 1 kV when properly measured. The RF content allows
much longer arcs to be sustained than expected.

 

[neon]

to answer your question 25kv can kill provided there is the current available to do so. on tv usualy there is a big value resistor in series with it so when you getz apped the current is limited to to ha-shit again. the arcing requires both current and voltage voltage to ionize the air and current to substain it actualy shock waves are exactly generated by discharge a large amount ot current. finaly there is no V A to define arcing too many dependents air moisture dust you name all come into play.