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Re: [TowerTalk] Vacuum tube 100 years old today

Subject: Re: [TowerTalk] Vacuum tube 100 years old today
From: Bob Nielsen <>
Date: Tue, 16 Nov 2004 10:10:03 -0800
List-post: <>
On Tue, Nov 16, 2004 at 11:28:11AM -0500, Tom Rauch wrote:
> On Nov. 16, 1904 Fleming patented the Fleming valve. The
> vacuum tube is 100 years old today (exactly 46 years to the
> day older than I am).
> I was an electrical engineering student in the late 60's.
> The electronics lab stock room was full of tubes and
> sockets, and our benches had 300 volt power supplies. About
> 50% of our inventory and study was tube related. I built a
> complete 500 watt HF station, receiver and transmitter, from
> stock room parts in my spare time. Every component necessary
> was in the stock room. From a textbook I still use,
> "Electronic Amplifier Circuits" McGraw-Hill Electrical
> Engineering Series 1961, comes the following quote:
> "For many applications a relative newcomer, the transistor,
> is replacing vacuum tube types because of the greater
> inherent reliability, lower power consumption, and smaller
> size. However, the complete replacement of the tube by the
> transistor does not seem likely, for the latter has
> shortcomings at high temperatures and high radiation
> intensities and in the production of high power at high
> frequencies. "
> About ten years later I received a call asking if I wanted
> any of those old tubes, tube related books, or HV bench
> power supplies before they hit the dumpster.

I was taking a senior physics class in electronics at UCLA in 1962 and
we spent some time studying vacuum tube circuits.  The professor was
asked if we were going to learn anything about transistors and replied
that he had never studied them himself, since he felt that they were a
fad which wouldn't last.

Bob N7XY

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