Greg,

One item you need to know is the maximum working altitude.  At low air
pressure, arcing and corona are a serious problem. 30KV is certainly
going to produce corona if there are any sharp points.  Conformal
coatings help - make sure the material can withstand the HV and ozone
production without degrading significantly.

You have to assume that dirt is attracted to the board due to static
field effects.  The conformal coating makes sure that the dirt can't
short out the board.  Look inside any TV monitor and you will see that
they are filthy after a few months of operation but they keep on
working.  That's good design.  Also, assume that this dirt reduces
heat being shed by the parts (forced or natural convection effects are
reduced as dirt is not a good heat conductor.

Just be as conservative in your design as $$$ will allow.  (and keep
your fingers away and my favorite rule around HV is that I always keep
one hand in my pocket at all times [across the chest HV is deadly
stuff!)

Bob

----- Original Message -----
From: Greg Kaskey <[log in to unmask]>
To: <[log in to unmask]>
Sent: December 15, 1999 10:07 AM
Subject: [DC] PWB High Voltage Material Choices?


All,

I hope you are doing well.

What PWB Material do I call out for one that is 0.074 inch thick and
it does
High Voltage Multiplying with 30K Volt Output?

The board has no solder mask and is encapsulated in a "Black, Rubber
Like
Material".  Also, the Board looks like it has some kind of clear
coating that
does not remind me of a "normal" protective coating which is applied
to the
entire finished assembly; it is soft vs. hard and can be easily
scraped off.

What questions would I need to ask to determine some of the material
choices?

Thanks for Helping,

Greg Kaskey
Sector Electronics, Inc.
V: 770-955-8044
E: [log in to unmask]

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