Zener noise / oscillations

Jul 23, 2012 143 Replies

If only!

The only monitor I designed incorporated width modulation using a Darlington series regulator controlling the voltage to the HO stage, with feedback derived from beam current. Rock steady size with a raster half height peak white, half black. That used a diode-split FBT.

Consumer designs (yecch!), using transistors, used a cheapo arrangement of a resistor in series with the supply, so the scan decreased with increased current draw, compensating for the increase in deflection sensitivity when the HV went down with increased beam current. Not perfect, but good enough for consumer TV.

Triplers were superseded by diode split windings, sometime in the 1980s.

Tube HO drive looked like a pulse with a (small) ramp sitting on top. That went away when tubes did. Transistor drive is just a rectangular pulse. Don't forget, also, that the output device (tube or transistor) is on only during the second half of the forward scan. The first half is supplied by the stored energy in the inductance circulating via the efficiency diode, both for tubes and transistors.

The thyristor HO scheme, developed by Siemens, was *really* weird, with a separate commutating coil. but still using Blumlein's inductive flyback principle for the actual scan. I had the original application notes, but they've long gone.

"For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)

Freudian slip?

;-)

-- "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)

All my 7000 series have green P31 phosphors, with blue filters. Background looks blue. Even the 7104, with an MCP CRT. I do have a 7603 storage that only ever gets used with spectrum analyzer plugins. That has a P31 phosphor, with a yellow (ish) filter, similar, I suppose to yours.

I guess I'm just so used to blue filters, I assume everything uses them.

"For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)

Aren't all "Zeners" above ~5.6V actually avalanche diodes?

Somewhere around there.

-- "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)

Yes, but everybody still calls them zeners.

John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators

It makes a difference when you're discussing negative resistance, which accompanies avalanche breakdown, but not, AFAIK, zener breakdown.

"For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)

Too tired to look at what I typed. I haven't slept more than four hours a night, in over a year. Sometimes I forget to hit the spell check button.

OTOH, I have seen more than one rectifier on fire. Big, stinking Selenium stacks with flames & sparks shooting out all over the place.

radiation.

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That is (obviously) glass and not metal and is small; looks similar to their GV3A; the catalog easily available online (courtesy of Syd Levine of Analog Services) does not list the HV series.

There is NO transistor that can take 1500V reliably; and at $2 each? FURRgeddit sez the FURRy Baer.

Oh, i remember them well; to use _that_ effect is way off datasheet specs.

Misspelt: s/b RectumFier with preparation H.

Check; yellowish phosphor and orangish graticule. I invert colors to be more readable and less ink to print; can convert then to B&W for "publication" if need.

Check. Helps to make for confusion.

Yea, did not look at very many

  • He wore THOSE??

On a sunny day (Mon, 30 Jul 2012 21:48:16 -0700) it happened Robert Baer wrote in :

I am sure I had some? google: transistor Vce 1500

Hundreds of links

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switching transistor Ic 5A-datasheet.html

The ones I had (or have, seen some recently in a box) are for TV horizontal output. Large current, fast switching, low beta. Probably not suited for low current stabilizer. But they do exist.

output.

This is the highest voltage one that Digikey has in stock (I think, anyway)

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Best regards, Spehro Pefhany

"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

output.

Here's one I've never seen the likes of before. Vcs (not a typo!) 2200V

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output.

Cascodes!

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Best regards, Spehro Pefhany

"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

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