Re: Old Berkeley Physics Labs

[Roger Haar <haar@PHYSICS.ARIZONA.EDU>]

Bob,
        At the U of Arizona, we use these.  Ours usually
have the B and C knobs set to about the same
angle, which provides different voltages.  The
total accelerating voltage is B+C, but the beam is
de-accelerated by the B for focusing.

        I will send you directly a pdf file of the
experiment we do that contains
a description of the tubes internals and workings.

Thanks,
 Roger Haar


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Bob Muir wrote:
> I just dredged up from a dark corner some of the equipment and
> manuals for the Berkeley Physics Labs of the '60's and '70's.
>
> I connected the crt (3BP1) as per instructions to an original
> powersupply.
>
> I get a beam, but am unable to focus it to a spot smaller than about
> 1/2 cm across.  The smallest spot is obtained with very little bias
> voltage (instead of the suggested 4 1/2 V) and very little voltage on
> the first grid (C+).
>
> There is negligible ripple in both the C and B power supplies.
>
> If anyone has experience with this CRT and can suggest how to focus
> better, I will appreciate a response off line to the e-mail address
> below.
>
> Thanks!
>
> ----------------------------------------------
> Bob Muir                      muirrob@uncg.edu
> Physics & Astronomy           336-334-3255
> UNC Greensboro, NC 27402-6170
> ----------------------------------------------
> Life is NOT a dress rehearsal.
> The trouble with reality is -- it's never the
> way you imagine it! -- Moira (For Better or
> for Worse)