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From: sunny@sun.uucp (Ms. Sunny Kirsten)
Newsgroups: net.consumers
Subject: Re: are ion generators bad for machinery and other living things?
Message-ID: <2280@sun.uucp>
Date: Thu, 6-Jun-85 22:20:04 EDT
Article-I.D.: sun.2280
Posted: Thu Jun  6 22:20:04 1985
Date-Received: Sun, 9-Jun-85 01:53:10 EDT
References: <4147@allegra.UUCP> <2221@sun.uucp> <2211@ncrcae.UUCP> <1027@dual.UUCP>
Organization: Sun Microsystems, Inc.
Lines: 26

> > As a EE with quite a bit of experience with CRT design, I have *never* seen
> > the cathode put at a high negative potential while the anode is grounded.
> > I think if you check, your SUN and other CRTs run a second anode potential
> > at around 12kv to 20kv, with the cathode grounded (or near ground ).  This
> > makes the circuit design in driving the grids or cathode with video
> > information much easier.  Remember, there is about a quarter inch of glass
> > between the phosphor an the front of the tube which is enough to prevent
> > a shock hazard.
> 
> Many old Oscilloscopes were designed with the cathode at a negative
> potential.  These were typical vacuum tube designs.  The anode was
> connected to about 200 Volts, the supply for the rest of the
> circuitry.  The deflection plates were connected to differential
> drivers.  The cathode was connected to about -1kV.  I made one of these
> in the dim and distant past.  There is also a similar design in 1966
> RCA receiving tube manual.  I have, however, never seen a T.V. type
> display designed this way.

Silly me, my Heath Tube Scope is exactly what I was thinking of as I originated
this insanity about innards of monitor circuitry, and that certainly isn't
the way most modern solid state monitors are built, just as the corrective
articles previously indicated.

				Sunny
-- 
{ucbvax,decvax,ihnp4}!sun!sunny (Ms. Sunny Kirsten)