Text with *** from Bob Pease, in response to Roy Johnson
At 04:50 AM 7/26/2009, Roy wrote:
Joe,
Very many thanks for sharing the personal and Philbrick sites.
I have spent a long time admiring them and realise many shared interests.
I have always been a fan of Gas tubes since designing a dekatron and gas thyratron counter in the early 1950s for a radiation meter. They may well be capable of further development which was truncated by the coming of the transistor.
My "association" with Philbrick dates from the early 1960s in the U.K. where I was using operational elements to process signals in aerodynamic turbulence research. Initially the modules were tube (valve) devices and the applications simple - such as integration over several minutes using dekatron counters and relays. Subsequently squaring, multiplication and correlation functions were developed.
Before Teledyne-Philbrick established their own office in the UK, the agents were A.E.P. International. Both offices were close to Heathrow airport. The module documentation and application notes were excellent and I still have some from that period.
My collection of Teledyne-Philbrick-Nexus modules includes
1017
101101
4252
4701
P55A
FLA-1 (Nexus)
SA-1 (Nexus)
SQ-10a (Nexus)
At first the only real competitors in the solid state area were Analog Devices and Burr-Brown, but UK companies quickly started to match some of their performances. Ancom, Computing Techniques and Amplicon produced some good items before integrated circuits were developed.
I have not tested any modules recently - it would be interesting to know how they perform after 40 years. Were electrolytic capacitors used? One would need to bring up the voltage current-limited slowly, before full voltage application. Perhaps when I get time ................
Thanks again for telling me of your excellent sites,
Best regards,
Roy
On Jul 27, 2009, at 9:25 PM, Joe Sousa wrote:
Roy,
Interesting to hear your experience with Philbrick and other contemporary engineering efforts.
I don't remember seeing electrolytic caps in solid state modules. Perhaps Bob Pease, who designed some of them remembers. Dan Sheingold or Alan Risley may also remember.
Regards,
-Joe
From: Robert Pease [mailto:czar44 AT me DOT com]
Sent: 28 July 2009 07:24
To: Joe Sousa
Cc: Roy AT mendit.org; Sheingold, Dan; Alan Risley; Robert Pease
Subject: Re: Caps in Philbrick modules
*** Hello, Friends,
I don't normally like to add one paragraph on top of 20, so I'll do this just once:
Philbrick and Nexus usually put in 0.01 UF P.S. bypass caps, in potted modules. They were generally reliable. We rarely had any problems; nor our customers.
We rarely even recommended 2.2 or 10 or 22 UF as bypasses, NEAR the op-amps. Maybe the customers figured out for themselves, to do this, in critical places? I bet the P45 needed some 2 UF or more. But I wrote the datasheet, and I don't recall mentioning it. I haven't got a P45 or PP45 datasheet near by.
The SP656 had a 330 UF Sprague 150D tantalum, in the main chopper filter; but that was rare. Most other modules, potted, or not ( P or SP) had no electrolytics or tantalums.
Best regards. / rap
OH YEAH: The 4701 VFC had a 3.3 UF tantalum on the "summing point", as the main integration filter; but it never got any transients. It was protected and limited to 1 volt or 1 mA. The 4705 or 7 or 9 had no electrolytics.
The 4702 FVC had a 1 UF as a little filter, near the output's summingpoint, and it, too was well protected. We _NEVER_ had problems with those.
All I can think of. / rap
Cc: Robert Pease <czar44 AT me DOT com>, k2w AT philbrickarchive.org
From: Robert Pease <czar44 AT me DOT com>
To: Roy
Subject: Re: Caps in Philbrick modules
Date: Tue, 28 Jul 2009 20:38:07 -0700
On Jul 28, 2009, at 12:24 AM, Roy wrote:
Dear Dr Pease,
Many thanks for the rapid and helpful response.
I'll have to wind some of the modules up when I get a chance - I bet that they will be fine!
*** No doubt.
Tant caps have had a bad press, but I suspect that comes more from the radio experience than the industrial areas where I can only recall seeing one failure in a psu.
*** Some of the bad press on Tantalums came from people buying the CHEAPEST available caps. We didn't do that. At Philbrick, we bought almost entirely from Sprague.
*** Some of the bad press ALSO comes from having a tantalum across thePS Busses when power is switched on FAST. Apparently the fast turn-on transients are bad for Tan Caps if there is no series R to limit the I. Mil-Specs say you need to put in the R.
As a matter of principle I always added a few uF and a 0.1 close to the socket.
Never does harm - may do good.
Many thanks for your comments (and for the excellent designs!)
*** Have fun! / Best wishes. / rap
Best regards,
Roy
P.S. Thanks, Joe, too for your response.
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