Re: Floating Scopes

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Winston,

On 4 Dec 2002, at 19:27, Tesla list wrote:

 > Original poster: "Winston Krutsch by way of Terry Fritz 
<twftesla-at-qwest-dot-net>" <u236-at-earthlink-dot-net>
 >
 > Hi All,
 >
 > 	I just bought a cute little Tektronix model 321 scope.  It is rated to
 > only 5 MHz, but that's OK, since it's battery powered, and was built
 > before 1963 :-)).  It's all solid state, too (not sure if that's good or
 > bad, yet).
 >
 > 	Anyway, I was wondering if I could stick this thing on the inside of my
 > toroid for making topload current measurements, without letting out its
 > smoke.  I'd then view the screen from the coil's controls via binoculars
 > ;-)).  My gut says "no", since the scope's components use the case as a
 > ground, and RF might make things a bit messy.  Comments???  I know I
 > could float it at a high DC potential, but I'm not sure about RF.

Not if the scope is mains-powered. Nothing must be outside the
topload if the Faraday Cage protection is to work. There will be
topload potential impressed across the scope's power transformer and
of course, the topload would be effectively shorted to ground.

Regards,
Malcolm


 > 	At any rate, I'm glad that I don't need to haul my Tek 545 outside
 > anymore, unless I need to make high frequency measurements ;-)).  Also,
 > did Tektronix make any battery powered tube scopes?
 >
 > Thanks,
 > Winston K.
 >
 > PS-I got the thing for $50, because there was something wrong with it.
 > When I took the case off, the "problem" was that both of the horizontal
 > plate connections to the CRT had been disconnected!  I put them back,
 > and all was well :-)).
 >
 >
 >