[Boatanchors] Question: X-Rays from 3B28?

Scott Johnson scottjohnson1 at cox.net
Sat Feb 14 15:19:36 EST 2015

Unless you are operating above 10kV, there is not an x-ray concern, and even
then, onles "soft " x-rays are present, the problems with x-rays manifest
themselves above 15 kV or so.  They should work fine at 450V, lower voltage
drop than a high vacuum type.  

Scott W7SVJ

-----Original Message-----
From: Boatanchors [mailto:boatanchors-bounces at puck.nether.net] On Behalf Of
Sent: Friday, February 13, 2015 8:42 PM
To: boatanchor
Subject: [Boatanchors] Question: X-Rays from 3B28?

Hello All,

Been thinking of using a pair of 3B28 tubes to rectify an output voltage to
around 450VDC.  That value is above the critical anode voltage value of 50V,
so that should not be a problem.  Current is less than the 500mA max listed
in the table.  With the output voltage far lower than the ~1000V values
listed in the table, I think these things would not even break a sweat.

Two questions for the experts:
1.  Any issue seen operating arund 450VDC?
2.  The tubes have a sticker on the base with a warning regarding x-rays.
Why is there a warning on the tube base but nothing shown on the data sheet?

I had no idea these would present an x-ray risk based on what I saw (and did
not see) on the data sheet, so I picked up a pair.  Perhaps this my learning
experience for the week.

Have a great weekend!

Best Regards,

Boatanchors mailing list
Boatanchors at puck.nether.net

More information about the Boatanchors mailing list