30 kV 10 mA power supply

[JoeBloe]

I think you mean KVA not KW Don.

Still incorrect.

 

[JoeBloe]

Luckily it's not both at once, so the real power
is much lower.

No shit.

 

[JoeBloe]

Modern large CRT displays
draw considerably more than that from the mains.

I have a 37" CRT display and it draws 350W. Of that 350W, I'd bet
that over half of it is used somewhere other than the anode supply.
Nearly 50W of it are used in the audio circuits alone (when fully
driven). Usage placards don't lie.

Just so you know, I have manufactured several products using the
biggest OEM flybacks available. Commercial products like 20kV oil
filtering tanks, among others.

Try again.

 

[JoeBloe]

Well, a carefully designed and wound 60 cycle transformer could do this,
perhaps with a doubler or tripler on the output side. The secondary would
have to be wound pi style to handle the potentials involved.

You're funny. Hahahahaha... Sure...

 

[[email protected]]

Yeh that would be some tripler!!

 

[Homer J Simpson]

You're funny. Hahahahaha... Sure...

Yeh that would be some tripler!!

And you are an idiot. So?



--
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+ damaged idiots.
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[joseph2k]

Nope.
Guess again.

Several kilowatts are usually involved in the horizontal scan of a large
screen tv. A special switching circuit first fills the deflection coil
with positive current for the right half of the sweep, resonates it for
a half cycle on retrace, and then returns the energy as a negative
deflection coil current for the left half of the sweep.

Gee, something seems unreasonable about the several kilowatts claim, my
brother's 65 inch draws less than 5 amps at 120 volts. My 27 inch TV draws
less than 200 VA or watts.

The energy is borrowed and returned to the power supply storage
capacitors. Only the small coil losses need be provided by the power
line. And nobody notices the few initial scans needed to get up to speed.

This is an extremely elegant energy efficiency conservation scheme that
has been in use for many decades. I first described it in a 1965 story.

Still the major power losses are in generating the deflection currents
rather than in energizing the CRT. Please note the vastly lower power
requirements for large screen TVs and displays that do not use CRTs.

 

[joseph2k]

joseph2k wrote:



I think you're thinking of an oscilloscope, where the beam currents are
very low, as you are only painting one line, and with a high-efficiency
phosphor, and no shadow mask.

In a TV-set type of CRT, the poor beam has to scan the whole screen,
and on a color set, a lot of the current ends up caught by the shadow
mask. A milliamp or two is more like it.

Projection CRT's use even higher current-- that's why they need liquid
cooling and heat sinks.

"Liquid cooling?" Which make and model are going on about. I have seen the
guts of scores of projector TV sets and high resolution displays (up to
3200 x 2400) as well; damn few even had a fan, the rest are convection
cooled.

 

[Tom Bruhns]

JoeBloe wrote:
....

Try again.

Since you didn't disagree with anything I put in the posting to which
you replied (or even the preceeding one), I don't know why you'd
suggest that. Perhaps you thought you read something in my posting
that wasn't there.

Cheers,
Tom

 

[Ancient_Hacker]

"Liquid cooling?" Which make and model are going on about. I have seen the
guts of scores of projector TV sets and high resolution displays (up to
3200 x 2400) as well; damn few even had a fan, the rest are convection
cooled.

I should have clarified-- in every projection TV I've seen the face of
the CRT has glycol liquid in front of it. The heated liquid rises to
the top where there's a heatsink to convey the liquid's heat to the air.

 

[JoeBloe]

And you are an idiot. So?

You're too goddamned retarded to even know how to answer the right
post... Yet you are calling me an idiot. Sure...

 

[JoeBloe]

JoeBloe wrote:
...

Since you didn't disagree with anything I put in the posting to which
you replied (or even the preceeding one), I don't know why you'd
suggest that. Perhaps you thought you read something in my posting
that wasn't there.

Cheers,
Tom

Your remark was more than a bit ambiguous "more than that from the
mains..."

More than what? I assumed you meant the 350W number. If so, your
assertion was incorrect. Granted the largest of the CRT family out
there does draw more than 350W, but I used my 37" as a good example.