[ARC5] OD3 VR Tube

[J. Forster]

In fact, the reason for using neons might not be because of diode
unavailability.

The inductive kick comes from the sudden opening of the circuit, and V=L
dI/dT applies. The neon lights allow a higher voltage to appear across the
coil, so the magnetic field collapses faster and the relay releases
faster. A diode or RC snubber would slow the coil release.

-John

==========




>
>
> I remember two incidents involving gas filled devices that stay in my
memory.
>
> First is the ARC-27 Collins built aircraft UHF radio.  There was some
NE2 type neon lamps across several relays in the set as I recall that
were suppressors for the "inductive pulse" that happens across the
armature coil
> when it is de-energized.  (In those days using silicon diodes for this
purpose was unknown!)  A couple of times I remember our "Shop expert" on
the
> ARC-27 was stuck with sets that worked "OK" when the outer housing was
removed but had glitches when the housing was replaced and pressurized!
It
> turned out to be the "Photosensitivity" of certain of the neon lamps in the
> set.  As "Jimmy Hunt" said about the problem: "The damned lamps are
scared of the dark!"
>
>
> The second case involved a "Mobile telephone decoder" which decoded the
assigned telephone number of the VHF FM mobile telephone and rang a
bell/buzzer when that set had an incoming telephone call.  Ma Bell used
a mechanical device to do that job with the Motorola radios, but CMC
(Canadian
> Marconi Company) designed an electronic device to do the same job that
was more compact and had no moving parts.  The decoder used cold cathode
triode
> subminiature tubes.  In order to do away with the "photoelectric"
effect, again, NE-2 type neon bulbs were illuminating the tubes in order
that they worked properly in darkness of an automobile trunk and the
housing for the decoder.  These exhibited some very weird operation when
the neon lamps failed at times!  Not always this happened, but enough
times to drive you nuts until you got the dim or non working neon lamps
replaced inside the decoder!
>
> That's my "gas filled devices" in the dark story.  Maybe the old "VR"
tube regulators sometime do the same thing in the dark?  I never had any
trouble,
> but then maybe I was always lucky?
>
> 73,
>
> Sandy W5TVW
> -----Original Message-----
> From: John Hutchins
> Sent: Friday, November 09, 2012 9:14 AM
> To: arc5 at mailman.qth.net
> Subject: Re: [ARC5] OD3 VR Tube
>
> All -
>
> "--> For one thing, VR-tubes must be able to have some input from light
to "encourage" the formation of the internal "plasma" "  <---  What
that's a new one?
>
> Lighter side:
> So the question is: Does a VR tube work in the dark, completely shielded
from any form of radiation ?
> Similar to : does a tree falling in the forest make a sound....
>
> Hutch
>
>
>
>
> On 11/8/2012 3:06 PM, Kenneth G. Gordon wrote:
>> For one thing, VR-tubes must be able to have some input from light to
"encourage" the formation of the internal "plasma"
>
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2013.0.2793 / Virus Database: 2624/5883 - Release Date: 11/08/12
>
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>