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| Thread ID: 23188 | 2002-08-09 10:44:00 | A diversion... Analogue Computers | Terry Porritt (14) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 69756 | 2002-08-09 10:44:00 | Poppa John in another posting mentioned he had maybe read about a vacuum 'toob', ie valve, computer circa 1938 . If so this was probably an analogue computer, as they had been around from the mid 20s when valve were used to make high gain amplifiers, ie op-amps . They were further developed during the war . One that I was involved as a team member in building during 1956/7 was at Joseph Lucas Gas Turbine, and it was quite advanced for the day . At that time you had to build your own, if you wanted performance . From memory it 24 high gain amplifiers that could be wired as either integrators or differentiators, 10 turn pots were on the inputs, and the valves, again from memory were the fairly new EF86 . A patch panel was used for wiring the system . In those days, complex systems were analysed using the method of linearizing for small perturbations, and so for example a jet engine fuel system /engine could be represented by an nth order differential equation . Early jet planes like Vampires and Meteors were somewhat unstable and the pilot was continually adjusting the throttle to keep constant rpm with changing altitude and Mach number, whilst at the same time steering a delicate course between engine surging and stalling during acceleration . Flame-outs were not uncommon, particularly in hot desert conditions . The analogue computer we built could either be setup to behave as an engine, or as a fuel system . Our electronics lab was directly over the basement test cells . Several of the staff were ex-RAF so it was only natural to use ex-RAF R1155 receivers and T1154 transmitters to communicate between the two departments :) Output from the computer was fed into a lab built very, very, high speed real time X-Y plotter, servo controlled, with the pen driven by taught Bowden cables and pulleys, again nothing like that could be bought . Most often the output was the response of the system to a step-function input, which represented the pilot suddenly opening or closing the throttle . Interesting days of Otis King slide rules, hand wound mechanical calculators, even electric Monroe mechanical calculators, 6 or 8 figure log tables . How would the young lads of today cope if transported back to that time? ;) |
Terry Porritt (14) | ||
| 69757 | 2002-08-09 10:57:00 | The good old days . . . . I cant profess to have experience that far back, but did do quite a bit of analogue servo control with valves . Have still got quite a lot of valve equipment, never use it though . 100 watt modulator using push-pull KT88's, silver plated lecher-line tuned 144 MHz transmitter 200 watt linear amplifier using 807's with a 1 . 5 kV power supply . Receiver from a japanese WW2 submarine with plug-in coil units to band change Hallicrafters SR80 Transceiver Slightly newer, A Toshiba T1000 laptop running MS DOS 2 . 2, 512kb ram, 1 FDD (720k) Wont accept XP though, cant find a place for the CD (Parry could suggest somewhere . . . ) |
godfather (25) | ||
| 69758 | 2002-08-09 11:01:00 | I think Poppa might have seen one of them at the Battle Of Hastings, 1066..... evidently, according to one of the other threads, he WAS there. | Baldy (26) | ||
| 69759 | 2002-08-09 11:05:00 | > How would the young lads of today cope if > transported back to that time? ;) well... ummm... I took apart an 8088 once... and ummm... I've programmed in BASIC... ummm... <grows old and dies> Mike. |
Mike (15) | ||
| 69760 | 2002-08-09 11:09:00 | Terry Porritt.. Oh the memories!! Same here with the Sliderules. Log tables. Algebra & Tryg. When "Handheld" Calculaters came out, they weren't allowed in the Exam Room. I would be lost without one now. Re the Valve Computer, maybe that was the one I was thinking about, I believe it was Massive very basic. Poppa John |
Poppa John (284) | ||
| 69761 | 2002-08-09 11:11:00 | I'm not really THAT old, its just that I was very young when I was born. | godfather (25) | ||
| 69762 | 2002-08-09 11:14:00 | I've got this big old radio sitting on my shelf next to my 3' high computer speakers... its big and white, got three big knobs on the front, and if you turn it around it doesn't have a back on it and inside its got lots of things that look like half-size lightbulbs. Mike. |
Mike (15) | ||
| 69763 | 2002-08-09 11:15:00 | > I was very young when I was born. you too? so was I! Mike. |
Mike (15) | ||
| 69764 | 2002-08-09 11:18:00 | Baldy, You'll keep. Poppa John :D :D | Poppa John (284) | ||
| 69765 | 2002-08-09 11:22:00 | Poppa John is the one on the right, here (www.battle1066.com) with the computer operated sword. | godfather (25) | ||
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