One problem with PIN's is if the RF voltage
the PIN is subjected to in its "off" state exceeds the
bias applied to the PIN to turn it off, the RF voltage will
attemp to turn the PIN back on.
In the limited ampunt of PIN diode work I've done here
it seems the PIN "off bias" should be at least twice the
applied RF voltage if any sort of SWR may be
present. So in a 50 ohm circuit at 1500 watts you'd need
about 5-600 volts reverse bias. In a Hi-Z cicuit such
as a plate tank I.E. 2000 ohms, you'd need about 3500 volts.
Thats a tall order.
73, Mark WB8JKR
On Wed, 18 Jun 03 13:10:12 -0700 2 <2@vc.net> writes:
> >Hi Rich,
> >
> >PINs are readily available to 1000Vpk and of course can be placed
> in series
> >for higher voltage applications.
>
> ** Hello, Steve -- For 10kW @ 50-ohms, a minimum piv of 2000v is
> needed.
>
> >Remember, a PIN is not a P-N junction
> >device and doesn't really have a "PIV" rating...when biased OFF,
> its a large
> >value resistor and when biased ON, it's a small value
> resistor....using
> >power devices that can be biased ON with amperes of current, that
> resistor
> >can become *really* small......-WB2WIK/6
> >
> >"Success is the ability to go from failure to failure with no loss
> of
> >enthusiasm." -Winston Churchill
> >
> >> -----Original Message-----
> >> From: 2 [SMTP:2@vc.net]
> >> Sent: Tuesday, June 17, 2003 7:15 AM
> >> To: Dr. William J. Schmidt, II; on4kj; AMPS
> >> Subject: Re: [Amps] electronic switching
> >>
> >> >Well, we do..... there are diodes that will handle as much as
> 10kW....
> >> but
> >> >they are expensive. Harris uses them in their gear...
> >> >
> >> ** What is the piv rating of such diodes, William?
> >>
> >> >Sincerely,
> >> >
> >> >Dr. William J. Schmidt, II K9HZ
> >> >
> >> >"Collector of Edison Wind-up Phonographs... Do you have one for
> me?"
> >> >Email: bill@wjschmidt.com
> >> >Alternate Email: wmschmidt@charter.net
> >> >WebPage: www.wjschmidt.com
> >> >
> >> >
> >> >
> >> >----- Original Message -----
> >> >From: "on4kj" <on4kj@skynet.be>
> >> >To: <amps@contesting.com>
> >> >Sent: Sunday, June 15, 2003 2:44 PM
> >> >Subject: [Amps] electronic switching
> >> >
> >> >
> >> >> Hello Folks,
> >> >>
> >> >> About steatite wafers used for band switching.
> >> >> Why dont we see switching systems based on pindiode, for input
> ( 100 w
> >> )
> >> >> must be possible nowadays. Even for high output power !!
> >> >> What say ?
> >> >>
> >> >> Jos on4kj
> >> >>
> >> >>
> >> >> ----- Original Message -----
> >> >> From: "Osten B Magnusson" <sm5dqc@algonet.se>
> >> >> To: <amps@contesting.com>
> >> >> Sent: Saturday, June 14, 2003 10:35 AM
> >> >> Subject: [Amps] 572B's WARNING
> >> >>
> >> >>
> >> >> >
> >> >> >
> >> >> > STAY AWAY FROM RICHARDSON ELECTRONICS, ENGLAND
> www.rell.com
> >> >> >
> >> >> > 572B's are sold here in Europe by different dealers, the
> tubes are
> >> >> distributed by Richardson Electronics in England, and they
> claim that
> >> it's
> >> >> Cetron tubes manufactured for National. Sorry to tell, but it
> isn't the
> >> >> truth - it's newly produced Chinese tubes re-badged by
> Richardsons as
> >> >> National and also have ''Made in USA'' printed on them. So be
> careful,
> >> >> before buying. I have been offered, not by Richardsons, but by
> the
> >> >> distributor to get a full refund if sending the tubes back.
> Richardsons
> >> >does
> >> >> not even answer e-mails...
> >> >> >
> >> >> > This is part of an e-mail from a serious distributor in
> England:
> >> >> >
> >> >> > >>Hello Osten,
> >> >> > >>Taylor is a brand name for RF parts but these can be
> re-badged
> >> >any
> >> >> type!
> >> >> > >>We have National 572B which are badged by Richardsons
> which is
> >> >the
> >> >> main
> >> >> > >>outlet for Eimac, but need not be Eimac !
> >> >> >
> >> >> > There are original Cetron NOS 572B's available here in
> Europe, have a
> >> >look
> >> >> at www.clhi-fi.it It's in Italian, but click on
> ''Surplus'' and
> >> than
> >> >> ''avanti'' to go to page four. There are no prices on the WEB,
> but in
> >> an
> >> >> e-mail they asked 500 ''euros'' for a matched pair, plus
> postage.
> >> That's
> >> >> totally USD 645 for a matched pair!!! I know that there are
> also NOS
> >> >> Cetron 572B's available in USA, but unfortunately we have to
> pay more
> >> >> postage, customs, 25 percent VAT etc. so here we always try to
> buy from
> >> a
> >> >> European Community country, this was no customs and other
> extra charges
> >> to
> >> >> pay.
> >> >> >
> >> >> > Probably time to get all ''glass tubes'' amplifiers marked
> ''junk''
> >> and
> >> >in
> >> >> the future only get amplifiers with ceramic tubes!
> >> >> >
> >> >> > 73 de Osten SM5DQC e-mail: sm5dqc@algonet.se
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