Re: Are deflection plates separate from the tube? Do Tek tubes use wehnelt caps?


Don Black <donald_black@...>
 

Here's a picture of the mercury delay lines for CSIRAC in Melbourne, Australia.s museum ,http://www.pcauthority.com.au/Gallery/299284,in-pictures-csirac-australias-first-digital-computer.aspx/14>. It's the world's oldest original computer still in working condition. Although it's normally on static display, it was saved complete and a few years ago restored to working condition again by volunteers, many who originally worked on it. It was first built in 1949 and improved in following years. Retired in 1966 (not a bad working life for a computer even by today's standards) it performed computations for over 1000 projects, the last for the futuristic ICI building opposite the Melbourne hospital. It's still a very impressive thing to see in the flesh. From memory there were about 30 mercury column delay line memories, see if you can count them.

Don Black.

On 19-May-13 3:30 AM, Robert wrote:
 

Sorry for the empty message, hit the wrong button.

Someone told me they worked on a 1950s computer that used a mercury pool as a delay line. One end would generate a wave and the other end would detect the wave with the transit time being the delay.

Try and get that around ROHS!
Bob

--- In TekScopes@..., "Robert" wrote:
>
>
>
> --- In TekScopes@..., Don Black wrote:
> >
> > What I call lumped (artificial) delay lines are delays made of a number
> > of discrete inductors in series with capacitors to ground (or the
> > complimentary side) rather than a cable using its natural inductance and
> > capacitance. In the case of the deflection plates, they are made of a
> > number of short segments coupled with small coils and trimmer capacitors
> > from each one (segment) to trim them). Of course you need a special
> > vacuum screwdriver to adjust them through the glass without losing the
> > vacuum (joke). Tektronix usually used a coiled coaxial delay line for
> > the signal delay to allow viewing the leading edge of a signal. However
> > artificial delays can also be used. We used to have a 3M dropout
> > compensator for video recorders which had to delay one horizontal line
> > of signal. I was switchable for the different standards, up to 100 µs
> > for 405 lines and it had row upon row of coils making up the delay lines.
> > Others more familiar with Tektronix please jump in and add or correct me
> > as you see fit please.
> >
> > Don Black.
> >
> > On 17-May-13 7:19 PM, cheater00 . wrote:
> > >
> > > Regarding delayed deflection plates.
> > >
> > > What is the basic operation of the lumped delay line circuits? Is it
> > > just a long delay cable with a network which compensates the
> > > impedance?
> > >
> > > Regarding the digital vs analogue cancer that spread into this
> > > conversation:
> > >
> > > On Fri, May 17, 2013 at 6:10 AM, Steve > > > > wrote:
> > > > Modern real time scope run up to 65 GHz. No analog scope could get
> > > within an order of magnitude of that. And few applications simply look
> > > at a Y-T waveform. I use fast RT scopes every week for tasks such as
> > > decomposing jitter components in serial data streams running at 28
> > > gigabits per second. I can easily measure these down to 300
> > > femtoseconds, with an accurate resolution of 50 femtoseconds or so.
> > > Users buy digital scopes for their analysis capability, seldom as a
> > > replacement just to look at waveforms that an analog scope could do.
> > > >
> > > > I love old analog scopes for their place in history. They are fun to
> > > restore. It is not different then people who restore antique autos.
> > > May of these had design features that were decades ahead of their
> > > time. But no one claims that an antique auto has the utility or
> > > reliability of a modern car that gets you to work every day.
> > > >
> > > > The tasks that design engineers need to perform today simply can not
> > > be performed by an analog scope.
> > >
> > >
> > > Because everyone is just like you and has exactly your job, right? Let
> > > me tell you, in 100% of my use of an oscilloscope I don't need *any*
> > > of the doohickeys you mentioned. And even if I took the technical
> > > level of my work to the very frontier of what's being done today, I
> > > still wouldn't need any of it. Who cares about 300 picosecond jitter
> > > when designing analogue audio circuits? You've got to be out of your
> > > mind to think everyone needs 65 GHz bandwidth (so why bring it up at
> > > all). My area, audio circuit design, will forever be fine with a 200
> > > MHz bandwidth analog scope, maybe with minimal digital or analogue
> > > storage capabilities. There are loads, loads, loads other areas in
> > > technology which don't need *anything* provided by digital scopes.
> > > Electrical and electronic engineers of all kinds and types have needs
> > > that are simply not provided for by a digital scope, while the digital
> > > scope provides a lot of stuff they expressly do *not* need. The same
> > > goes for hobbyists: very few end up needing high bandwidth; if an eval
> > > board or kit is provided you don't need to care about clock lines
> > > being bad. There's a huge amount of those people, and I dare say many
> > > more than those who need 65 GHz scopes.
> > >
> > > It seems like you think the moment NASA started building the space
> > > shuttle everyone stopped building, using, and servicing bicycles. What
> > > a load of junk. Look at your wrist watch or your mobile phone. Think
> > > that needs a 65GHz scope to build?
> > >
> > >
> > > Please let's not derail this topic further. If you or anyone else
> > > wants to continue the DSO vs CRO conversation, open up your own thread
> > > (which I likely won't take part in).
> > >
> > > Kill it with fire.
> > >
> > >
> >
>


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