22 Apr
2005
22 Apr
'05
10:42 a.m.
From: "Scott Stevens" <chenmel at earthlink.net>
On Thu, 21 Apr 2005 09:31:08 -0700 (PDT)
Tom Jennings <tomj at wps.com> wrote:
I have a few 500 series plug-ins with nuvistors, and have found them to be
good reliable devices (you soon recognise the signs of a nuvistor on its way
out), I would have the nuvistor version of the 453 and 454 in preference to
the FET, but then I don't need to switch on a scope and use it immediatly.
The valve is much more tolerant of over voltage on the input.
I have seen a sub-minature valve that is about 1/4 of the size of the
nuvistor, it is a small ceramic triode, with gold pins, used in the RF stage
of radar receivers. one of my staff had a complete oscillator / mixer unit
mounted on a plinth on his desk (a present when he left the Air Force), the
unit was around 3" long and 3/8" diameter, which included the oscilator and
mixer cavities. The valve plugged in one end.
Jim.
On Wed, 20 Apr 2005, William Donzelli wrote:
Listers' favorite 'scopes, the Tek 5xx series, often have them in
the vertical plugins.
The first generation Tek 453, 'the version to avoid' has nuvistors in
the front end. The 453 and 454 are the last-generation Tek scope to not
include custom unobtanium semiconductors. - What
was/is the smallest tube? purpose?
RCA's Nuvistor - a family often found in late 1960s TV tuners and
some test equipments. They are almost always triodes, and are really
small - 3/4 inch long, maybe 3/8 inch diameter, all metal. RCA made
a few half sized Nuvistors, but never sold them.