Why do post-apocalyptic stories have old tube electonics?

[chico]

Every story you read/see/play about a post apocalyptic future involves tube tv's and things. Even ones that dont involve nukes.

Is this just holywood, or do tubes last longer than MOSFET based electronics?
Why do MOSFET electroncs fail? Limited number of switchings before failure?

What about linear regulators and the like? I have a linear PSU that is as old as my father, will it also work forever? The regulator gets hot so I figure it would break but it doesnt seem to.

 

[crutschow]

It's just Hollywood. Tubes fail at a much higher rate than solid-state (including MOSFET) devices. In the old days of tube TVs many stores had tube testers where you could bring your tubes when your TV stopped working to try to determine which one failed. You could usually figure on doing that about once every year or so.

If operated within their design limits solid-state devices last a very long time, likely longer than your lifetime. There is no intrinsic failure or wear-out mechanism. I have a 25 year old Sony TV there has never failed, and I'm sure many others have had that same experience. Most computer failures are from the mechanical hard drive, not the electronics.

 

[chico]

I know there is lots of hubub about solid state computer hardrives failing after a few thousand re-writes. Isn't this an "intrinsic transistor failure mode"?

 

[JimB]

However, depending on the nature of the pockyclipse*, if it was a nuclear war good old thermionic valves are generally impervious to high levels of radiation and EMP.

Solid state devices however are very susceptible to radiation and EMP and would very easily be sent off to silicon heaven**.

JimB


References
* Mad Max beyond thunderdome
** Red Dwarf

 

[crutschow]

I know there is lots of hubub about solid state computer hardrives failing after a few thousand re-writes. Isn't this an "intrinsic transistor failure mode"?

You bring up a good exception to my generality about the reliability of solid-state devices. Some solid-state non-volatile memories use a technique where the memory state of each bit is determined by the charge level on an isolated tiny transistor gate capacitor. To change the memory state they pass a charge (tunnel) through the capacitor dielectric with a relatively high voltage. This can have the effect of slightly damaging the dielectric each time the memory state is changed. Thus, after a sufficient number of memory writes (not reads), the dielectric may become leaky and the memory fails.

But this type of failure is understood and is an exception to the normal high reliability of solid-state devices.

 

[TiagoSilva]

Maybe because if there was one tubes are the foundation of electronics? Back to the old ways... And, why not, they can be easy made from a common lamp, by adding a grid and a plate... Or I'm I mistaken ?

 

[dknguyen]

It's because when they are covered in dust they are still recognizable as electronics, rather than just a dusty flat plate or board of nothing. It's that old rustic charm.

 

[carbonzit]

Maybe because if there was one tubes are the foundation of electronics? Back to the old ways... And, why not, they can be easy made from a common lamp, by adding a grid and a plate... Or I'm I mistaken ?

Make a tube from a common light bulb? Sure, if you have a vacuum pump and a glass plant: all you need to do is break the bulb, add the grid and plate, blow a new glass bulb, evacuate and seal it ...

Otherwise, no.

 

[TiagoSilva]

Make a tube from a common light bulb? Sure, if you have a vacuum pump and a glass plant: all you need to do is break the bulb, add the grid and plate, blow a new glass bulb, evacuate and seal it ...

Otherwise, no.

See this Lee De Forest - Wikipedia, the free encyclopedia

 

[carbonzit]

See this Lee De Forest - Wikipedia, the free encyclopedia

I saw that: so? Where does it say that one can make a tube (let's say a primitive "audion", or even a diode for that matter) from a light bulb without taking it apart?

 

[Ross Craney]

I saw that: so? Where does it say that one can make a tube (let's say a primitive "audion", or even a diode for that matter) from a light bulb without taking it apart?[/QUOTE

**broken link removed**

 

[TiagoSilva]

carbonzit:
It seems that you have not been around in the MacGuyver television series times... Oh well, that "give up" spirit makes the world the bright place it is today

 

[carbonzit]

carbonzit:
It seems that you have not been around in the MacGuyver television series times... Oh well, that "give up" spirit makes the world the bright place it is today

OK, so I'm curious: tell us how you'd go about making a triode from a light bulb (and anything else you might find around the house).

 

[TiagoSilva]

OK, so I'm curious: tell us how you'd go about making a triode from a light bulb (and anything else you might find around the house).

Depends on who's house and how much junk there's in Will I get anything from teaching you how to make a vacuum tube from a fluorescent light tube ??? If not... Get me some low plate voltage vacuum tubes triodes (medium mu) references and it would be a good payment

 

[Ross Craney]

OK, so I'm curious: tell us how you'd go about making a triode from a light bulb (and anything else you might find around the house).

see the link on post #11. Amazing what clever people can do.

 

[davenn]

see the link on post #11. Amazing what clever people can do.

yeah but the point is, he didnt make a triode from a lightbulb (globe) he created a tube from scratch. still very awesome
if you take an existing light globe, you are going to have to break the glass seal to be able to insert the plate and grid, out from the filament a little way. Then evacuate it and reseal it

Dave

 

[carbonzit]

yeah but the point is, he didnt make a triode from a lightbulb (globe) he created a tube from scratch. still very awesome
if you take an existing light globe, you are going to have to break the glass seal to be able to insert the plate and grid, out from the filament a little way. Then evacuate it and reseal it

Right; thank you for getting what I was trying to say. I do have a certain amount of respect for those who can create technological stuff under adverse conditions (for example, figuring out how to develop photographic film in wartime in Vietnam in The Killing Fields.

However, there's also a lot of "folklore" (i.e., bunkum, BS, etc.) attached to some of these feats of MacGuyver-ism. For iinstance, this story about making a radio in a WWII Japanese POW camp really makes my BS meter twitch. Sure, it could have been done, but to me, it has all the earmarks of a tall tale. A rousing good one, mind you, with many tantalizing details and a heartwarming finish when the prisoners are at last able to tune in the BBC. Sorry, but color me skeptical.

 

[davenn]

However, there's also a lot of "folklore" (i.e., bunkum, BS, etc.) attached to some of these feats of MacGuyver-ism. For iinstance, this story about making a radio in a WWII Japanese POW camp really makes my BS meter twitch. Sure, it could have been done, but to me, it has all the earmarks of a tall tale. A rousing good one, mind you, with many tantalizing details and a heartwarming finish when the prisoners are at last able to tune in the BBC. Sorry, but color me skeptical.

well I know, from some that served in WW2 that were unfortunate prisoners in German POW camps that they did make receivers to listen to the BBC etc, that is very valid. (dont know about transmitters tho, as far as Im aware only receivers).

Making a receiver is relatively straight forward out of items commonly found around the place. You can make a point contact, detector diode out off just about any 2 dissimilar metal. When I was a kid (more yrs ago than I care to remember or tell) I made the real crystal set radio using a Galena crystal (Galena PbS = Lead Sulphide) and a wire touching onto it as the detector diode.

cheers
Dave

P.S. and my own comment on the OP ... and as others have hinted at. valve radio gear really is immune to EMP bursts that would just kill today's micro electronics.

 

[carbonzit]

well I know, from some that served in WW2 that were unfortunate prisoners in German POW camps that they did make receivers to listen to the BBC etc, that is very valid. (dont know about transmitters tho, as far as Im aware only receivers).

Making a receiver is relatively straight forward out of items commonly found around the place. You can make a point contact, detector diode out off just about any 2 dissimilar metal. When I was a kid (more yrs ago than I care to remember or tell) I made the real crystal set radio using a Galena crystal (Galena PbS = Lead Sulphide) and a wire touching onto it as the detector diode.

Except that this tale isn't about a crystal radio set: supposedly, they made a full-blown regenerative receiver with a single tube (the tube was smuggled in by someone who worked in the camp). The thing that I'm most skeptical about, and the description the most vague about, was making the rectifier to supply B+. And wires out of chicken wire, covered with fish oil and flour for insulation? And getting the thing to oscillate at a frequency even close to that needed to pick up the BBC? Hmmmm ...

So what accounts from POWs in German camps have you read?

 

[TiagoSilva]

Except that this tale isn't about a crystal radio set: supposedly, they made a full-blown regenerative receiver with a single tube (the tube was smuggled in by someone who worked in the camp). The thing that I'm most skeptical about, and the description the most vague about, was making the rectifier to supply B+. And wires out of chicken wire, covered with fish oil and flour for insulation? And getting the thing to oscillate at a frequency even close to that needed to pick up the BBC? Hmmmm ...

So what accounts from POWs in German camps have you read?

Story's tend to evolve into similar story's with time... Although, with some crafting skills one could build a coil very little space between each turn, that would work, bad, but it would. Capacitors, that can be made with the fish oil and paper. Tube or no tube... Hum...That could be folklore, instead they could have used a razor blade with a small graphite bar from a pencil touching the blade, that would work as a galena crystal, with proper adjustments... But this knowledge in that time... That I don't know. I guess the most difficult part to build would be the sound emitter... At least with a huge impedance... But if a coil was made around a small iron insulated (with paper) bar, with a small needle in the small end of a paper cone that would work. But then again, this radio would require a lot of space... The good part is that it would not look like one!

Nothing is impossible! This is what defines the very Human nature, explore, explore, explore!