Talk:Vacuum tube/Archive 4

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Archive 3

Archive 4

Could change name to thermionic valve

Vacuum tube seems too specific. They aren't all tubes and they don't all have a vacuum. Thermionic valve seems better ? - Rod57 (talk) 17:29, 9 April 2018 (UTC)

This article is written in American English, and the vast majority of what is described in the article are indeed tubes and do have a vacuum. Also, I believe in British English they are normally called "valves", not "thermionic valves". Jc3s5h (talk) 18:43, 9 April 2018 (UTC)

• Oppose. Vacuum tube is the WP:COMMONNAME. There are vacuum tubes (this article) and gas tubes (e.g., neon bulbs, voltage regulator tubes and ignitrons). Glrx (talk) 02:34, 10 April 2018 (UTC)

• Oppose per Glrx. Jeh (talk) 03:23, 10 April 2018 (UTC)

• Oppose as above, vacuum tube is the WP:COMMONNAME. There is a redirect from Thermionic valve, which is, I suspect the technical (physics) name.

Note, though, that many of what are called vacuum tubes aren't very tube shaped, but are historically included. The magnetron, commonly called magnetron tube, which makes your microwave oven work, is really tube shaped. Gah4 (talk) 08:06, 18 April 2019 (UTC)

Is charge flow correct?

This article states that electrons are emitted from the cathode; yet the Wikipedia articles on the Cathode and Anode state that electrons are emitted from the anode. Or, is it that electrodes in vacuum tubes can serve multiple roles: acting as anodes when heated, and cathodes when unheated? Please clarify. — Preceding unsigned comment added by 184.2.141.98 (talk) 14:39, 2 April 2019 (UTC)

Electrons are emitted from the cathode into the device. Electrons are therefore entering the cathode from the external circuit to replace them. SpinningSpark 15:49, 2 April 2019 (UTC)

The confusion comes in what is called conventional current. Conventional current is defined to be positive, so moves the opposite direction from electrons. Cathode and Anode explain this well enough. Gah4 (talk) 08:10, 18 April 2019 (UTC)

crystal rectifier

The article gives some advantages of vacuum tube rectifiers over galena point-contact rectifiers. One thing, though. In WW2 radar, which was mostly at 3GHz and 10GHz, point-contact detectors were needed as vacuum tubes can't go that fast. Research done during the war, and continuing after, led to the modern semiconductor industry. But yes, for broadcast radio frequencies vacuum tube rectifiers were a better choice. Gah4 (talk) 02:28, 30 January 2020 (UTC)

Whirlwind and reduced heater volatages

I've removed this text from the article;

SAGE computers were dual installations, with one operating, and the other in standby. To locate potential tube failures in the standby computer, heater voltages were reduced, which caused failures of tubes which would otherwise fail in service. These computers continued in service years after other tube computers had been superseded.

I think the editor has conflated two issues. In the operating computer, heater voltage was turned on and off daily to preserve tube life, with a steady ramp on each cycle to avoid thermal shock.[1] In the standby computer, the tube inputs were cycled through the extreme range of permissable voltages to bring on early failure of any "dodgy" units (marginal checking).[2]

This could be fixed in the article, but this might be something that is more applicable to the Whirlwind article. SpinningSpark 17:47, 12 May 2020 (UTC)

A variety of marginal checking could be done. My first thought might have been anode voltage, but filament voltage could also do it. I suspect that you would want to not vary them all at the same time, as that might mask some failure modes. Otherwise, yes, it does seem like it should go to the Whirlwind article. Well, slow filament power up should be generally a good idea, so that might go here. Gah4 (talk) 20:56, 12 May 2020 (UTC)

The source says they did both input and plate voltages (although their diagram only shows the test on the grid). SpinningSpark 09:42, 13 May 2020 (UTC)

Wrong Images

7 of the first 8 images in this article seem to have been replaced with photos of Honda SUVs. Xzelence (talk) 15:59, 23 July 2021 (UTC)