| Re: IBM system/360, whiz or dog? [message #399645] |
Wed, 09 September 2020 01:07 |
Charlie Gibbs
Messages: 5313
Registered: January 2012
Karma: 0
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Senior Member |
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On 2020-09-09, Dave Garland <dave.garland@wizinfo.com> wrote:
> On 9/8/2020 2:16 PM, hancock4@bbs.cpcn.com wrote:
>
>> It always puzzled me how certain fields things like part
>> numbers or engineering designations would be cryptic
>> alpha-numeric combinations. Like a vacuum tube code.
>
> Of course, at least in US usage, regular (diode/triode/pentode)
> tubes(valves) the number that preceded the letters designated the
> filament voltage. For the series string tubes of the cheap "All
> American 5" AM radio, those numbers added up to 121. I always figured
> the one or two letters were arbitrary but issued in sequence.
Rectifier tubes tended to be given letters near the end of the
alphabet. 5U4 was a popular tube: 5-volt filament, 4 elements.
(The number at the end was usually the number of elements in the
tube.) CRTs were different; the first number was the size of
the screen in inches, and the code usually ended in Pn, which
identified the phosphor. For example, 5BP1 was a 5-inch tube
with a green phosphor. Black-and white TV picture tubes usually
had a P4 phosphor, while shadow-mask colour tubes were P22.
P7 was a long-persistence phosphor used in radar displays.
> "Different" tubes followed other patterns, e.g. gas-discharge voltage
> regulator tubes were "VR" followed by the design voltage, e.g. VR150.
Sometimes this designation was preceded by a code similar to the
ones above; for example, VR150 was also known as 0D3. The zero
took the place of the heater voltage in tubes that had no heater.
--
/~\ Charlie Gibbs | Microsoft is a dictatorship.
\ / <cgibbs@kltpzyxm.invalid> | Apple is a cult.
X I'm really at ac.dekanfrus | Linux is anarchy.
/ \ if you read it the right way. | Pick your poison.
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