Re: O-scope question...

On Mon, 03 Nov 2008 21:29:21 -0600, Tim Wescott wrote:
On Tue, 04 Nov 2008 12:50:21 +1100, Phil Allison wrote:
"sbrehler"

I am looking to purchase a entry/mid-level O-scope and have been eyeing
a BK precision 2125A (30Mhz, Dual Trace, Analog).

http://www.testequipmentdepot.com/bk-precision/oscilloscopes/2125a.htm?
gclid=CKq61L7h2ZYCFQNvHgodDnLe2w


** Looks much like any other, low cost Asian made scope - except for
the inclusion of delayed sweep.

Like all of them I have seen, there is no mention of a magnetic shield
being fitted to the CRT - this means the trace will wobble or shimmer
if ever you bring an AC supply transformer near the unit. Nearly ALL the
famous brand US or European brand scopes have magnetic ( ie Mu Metal )
shields on the CRT to eliminate this.

Whether this matters to YOU depends on what sort of work you intend
doing and how you like to install the scope on your work bench.

Scopes are very much " horses for courses" and what one user loves
another will just HATE !!

Personally, I cannot bear to use a digital scope.

My 5MHz Heathkit scope has a mu-metal shield.

Or at least it has a shield of something that _looks_ like mu-metal.

Doesn't work for snot, though -- it wiggles all over in the presence of a
magnetic field. I think they just put something in there so it'd _look_
like it had a shield (either that, or there's something special about the
scope that makes it extra sensitive to mag fields, and it'd be tons worse
without the shield -- that's a scary thought).

I have an electric pencil sharpener on my desk next to my CRT monitor. You
should see the screen when I sharpen a pencil!

Cheers!
Rich


.

Relevant Pages

  • Re: O-scope question...
    ... BK precision 2125A (30Mhz, Dual Trace, Analog). ... the CRT to eliminate this. ... and how you like to install the scope on your work bench. ... My Tek TDS2012 doesn't have a CRT shield! ...
    (sci.electronics.basics)
  • Re: O-scope question...
    ... shields on the CRT to eliminate this. ... doing and how you like to install the scope on your work bench. ... My 5MHz Heathkit scope has a mu-metal shield. ... glass window as a mirror to find the de-mag button. ...
    (sci.electronics.basics)
  • Re: O-scope question...
    ... magnetic field. ... ** Tin plate shield - shields the sensitive internal circuity from ES fields from the X and Y plates. ... There is a very simple and reliable test for the presence of a Mu-Metal shield - first place the scope so the tube is facing straight up with the trace line centred. ...
    (sci.electronics.basics)
  • Re: The Aging Amateur Astronomer
    ... Shield ... An observatory or just some portable ... As everyone knows, it's very disheartening to spend time setting up the scope, drift aligning the platform, etc., etc., only to have some yahoo turn on his porch light and leave it on past midnight, night after night. ... Of course, there's one upside to all this cloudy weather - When it /does/ clear, I'm less likely to be dissuaded from observing by local lights! ...
    (sci.astro.amateur)
  • Re: O-scope question...
    ... a BK precision 2125A (30Mhz, Dual Trace, Analog). ... doing and how you like to install the scope on your work bench. ... My 5MHz Heathkit scope has a mu-metal shield. ... "Applied Control Theory for Embedded Systems" gives you just what it says. ...
    (sci.electronics.basics)
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