[GreenKeys] Transient voltage suppressers

[W2HX]

Doug, et. al. I would recommend against using these as they are made of selenium. I regularly remove selenium rectifiers from boat anchor gear. When it goes (and they do) they release toxic fumes (see Wikipedia). I think with all the modern suppressor technology available, I would use something more modern (and better) MOV, etc.


73 Eugene W2HX


From: GreenKeys [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of Ed Sharpe Archivist for SMECC via GreenKeys
Sent: Wednesday, March 25, 2015 11:31 AM
To: douglas-w-jones at uiowa.edu; greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] Transient voltage suppressers


here is a little info on them

http://so-much-stuff.com/pdp8/pdf/6rs20sp.pdf

ed#  www.smecc.org<http://www.smecc.org>

In a message dated 3/25/2015 8:14:58 A.M. US Mountain Standard Time, douglas-w-jones at uiowa.edu<mailto:douglas-w-jones at uiowa.edu> writes:
Teletype Model 33s use several GE 20SP4B4 thyrectors as
transient voltage suppressers.  I note that they are
currently available on Ebay from s source I know nothing
about.  They claim more than 10 available.  A bit pricey,
but I haven't seen these available very frequently.

There are also a pair of these in my 1965 PDP-8, one
across the mercury relay coil, the other across the relay
contacts.

-- http://www.ebay.com/itm/121419976637

        Doug Jones
        jones at cs.uiowa.edu<mailto:jones at cs.uiowa.edu>
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