Re: Which university produces good analog EEs?

But does modern design practice use vacuum tube logic circuits still?

Ah, now it registered ;-)

You've got mail.

--
Regards, Joerg

http://www.analogconsultants.com

Ah, but don't you recall that thread Win started a while ago? Didn't his solution involve a tube? ;-)

Tim

-- Deep Fryer: A very philosophical monk. Website @

The HV switch? I think he went the white-knuckle route using a FET stack. A ballast triode would probably have been the perfect fit. Problem is, they don't make'em no more :-(

--
Regards, Joerg

http://www.analogconsultants.com

Joerg snipped-for-privacy@removethispacbell.net posted to sci.electronics.design:

Ah but they do. High voltage (over 1000 V) vacuum tubes still popular. I think Win even used a tube solution for a 10kV ramp generator recently.

That was the one.

Tim

-- Deep Fryer: A very philosophical monk. Website @

Who? There are some tube mfgs and probably the largest ones are Sovtek and Svetlana but there ain't much in HV tubes there. It's all audio because that is where the big bucks can be made.

IIRC he opted for a FET stack.

--
Regards, Joerg

http://www.analogconsultants.com

...and some really nice HF RF linear power amplifier devices.

Jim

Ok, yeah, of course you can still get some of the really big tubes. But those aren't practical and economical for a small HV circuit while the old TV ballast triode might have been.

--
Regards, Joerg

http://www.analogconsultants.com

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Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Joerg snipped-for-privacy@removethispacbell.net posted to sci.electronics.design:

I am asking him.

Big tubes, CRTs and the like you can get from Western mfgs. But any regular tubes will be NOS.

--
Regards, Joerg

http://www.analogconsultants.com

Some of the HV stuff is still being made in small runs.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Cute trick: use an HV rectifier, like a 1B3, and control its filament voltage to make it an amplifier. I used to do that when I was a kid... flashlight battery, rheostat to filament (with long plastic shaft!), neon sign transformer, charging a bank of oil caps, with the loop closed manually. You could run the xenon flashtubes just below the point where they'd fire spontaneously.

Amazing I'm still alive.

John

One TV tech I worked with when I was 13 would reach into those old tube type color TV sets and grab the second anode lead, then touch someone. ONCE. Most people never got close to him again, after that.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Neat! I wonder what the achievable loop bandwidth would be ...

I guess many of us wonder about that. I remember dropping a tool into my

2nd shortwave power amp. BADABANG! 5kV on the plates and an oil-cooled transformer the size of a shoe box. It could push all the gusto of a 230V/16A circuit into the HV node if needed. The amp before that was built when I head no money for luxuries such as transformers so I rigged up a tripler from 230VAC to around 900VDC. Tons of caps, lots of power. Of course, German power plugs are not keyed ... One day one of the caps decided it was time. Ceiling lights dimmed, me scratching my head because there was no dimmer. Phssst ... BAM! The can had taken a chunk out of the ceiling plaster and whitish fluff rained down on me. Oh man, if I would have had my face over that amp.

--
Regards, Joerg

http://www.analogconsultants.com