and memory cards. Users of the last generation of industrial control equipment come to mind immediately. I maintain a couple of industrial touchscreen interface panels that store configuration setups on CF cards, but cannot support CF cards larger than 128 MB due to firmware limitations.
This is industrial strength hardware that that would take serious $$$ to replace, a lot of time to migrate the software and debug the interface for, and it is perfectly functional. The only problem is that the mass-market applications for flash memory (digital cameras and music players) have long since outgrown the 16 or 32 MB cards that are used to store machine setups. So memory card manufacturers no longer manufacture the smaller sizes, because the market is so limited. So users either have the choice of paying $$$ for obsolete memory cards from automation suppliers, or buying them (often for less than the shipping cost) on eBay.
, they are relatively "clean", and employ lots of white collar/upper middle class workers. Most communities were glad to have them built nearby. Especially, when they were helping "beat those commies to the moon".
A heavy steel forging operation, OTOH, would face opposition because of the smokestack emissions, and the ingrained idea that we don't need workers who actually MAKE anything anymore, when we can base our entire economy on shuffling money around and suing each other.
The heating caused by the electron beams hitting the aperture grille would cause the grill wires to expand slightly. If they weren't mechanically fastened together, the grille would warp out of shape enough to cause problems with convergence and purity.
, because hobby chemistry was pretty much destroyed well before 9/11. The "War on Drugs" caused most chemical sellers to eliminate sales to individuals, and in some states (like Texas) it is illegal to even own laboratory glassware without a permit (and regular inspections) from local police.
Add in the effect of lawyers and insurance companies (who drove chemistry sets off of toy store shelves), and you have one more "perfect storm" contributing to the ongoing "dumbing down" of the US.
First off, NOTHING is going to prevent serious damage in the case of a direct lightning strike onto the electrical wires feeding your house. The energy levels involved are far beyond what any type of household surge suppressor is going to handle.
The problem with installing surge suppression at the outlet is that the surge current being dumped into the far end of a grounded wire will simply cause the voltage on that end of the conductor to spike upwards, due to the conductor's resistance, and more importantly in the case of a fast risetime transient, the wire's inductance.
You now have the grounded case of the computer system or whatever you were trying to protect elevated hundreds or thousands of volta above earth ground. This voltage then looks for alternate paths to ground via ethernet cables, phone lines, or anything else plugged into it.
In fact, these type of devices can often provide a false sense of security for the user.
In order for a surge protector to function effectively, it needs a short. low impedance path to the building's main electrical service ground. Devices that plug in at the receptacle are connected to ground only through the branch circuit wiring, which may be a hundreds feet of more in length before it gets back to the main electrical panel. All that wire length adds resistance and inductance, which can completely negate the effectiveness of the surge protector. The situation is even worse in older buildings, where the receptacle ground may not even be copper wire, but the galvanized steel spiral armor on "BX" type cable.
The only surge protection that is worth a damn is installed (hard wired, by a qualified person) at the main building electrical panel, where the diverted energy can be dumped directly into the main building ground with a heavy gauge conductor. These type of units protect ALL the wiring in the building, rather than just selected receptacles.
Wall warts also allow product designers to accommodate regional variations in voltage/frequency/receptacle format by simply shipping the appropriate wallwart for the destination country. Avoids the problems with different power transformers, fuses, and cordsets for different countries.
That way, if the grid went down, there would be SOMEWHERE to dump the output of the alternator, at least until the plant can be shut down in a controlled manner.
Large backup generator installations have load banks installed so that the generator can be tested under load on a regular basis, without actually having to cut the facility power off of the grid.
"Bernie Sanders was supposedly further left than whole damn Green Party combined"
According to who? Sanders has been a bit of a disappointment, but then again, so has the rest of the Congress.
Bernie Sanders isn't even the farthest to the left in the US Congress (that would seem to be Dennis Kucinich). Kucinich really should consider jumping ship and joining the Greens, like Cynthia McKinney did. The Democratic Party machine is supporting several challengers to his congressional seat, probably as payback for being too vocal about impeachment and the various Bush regime atrocities.
Similar piece of hardware, but larger/higher powered.
Vibrators were used in vacuum tube car radios and other applications where high voltages were needed and only low voltage DC power was available. The vibrator was essentially a buzzer that was used to rapidly switch DC power on and off in the primary of a transformer, creating a pulsating DC which could be stepped up by the transformer and then rectified/filtered and used as the plate voltage for the vacuum tubes. They were constant trouble sources, with contacts that would stick (and blow the radio fuse), and they emitted large amounts of RF noise which had to be filtered out for the rest of the radio to work. Sometimes they wouldn't want to start without pounding the dashboard to get the weighted reed inside moving.
They were rendered obsolete once crude power transistors came along, allowing the audio power output stage of a car radio to be transistorized. The other stages of the radio could then use specially designed tubes that would operate at low voltages, or, in a few short years, they became fully solid state.
The electromechanical choppers that were used to stabilize op-amps in precision instrumentation were somewhat similar devices, but they tended to be more reliable because they only switched tiny signal levels, as opposed to the 15-20A typical of a car radio operated from the then standard 6 volt battery.
about the hydrazine fuel onboard, and the hazard it would pose to anyone on the ground, as if the fuel tanks would survive the breakup and atmospheric heating of the re-entry.
Looks like a great chance for the Bush regime to pull off an ASAT test, with a ready-made cover story to deflect blame for all the space junk it will create.
do electrical work on a building that they personally live in. If you own a building which you rent out, you are required to use a licensed electrician. Ditto for a building used for a business or other non-residential purposes. I believe the same goes for plumbing and other licensed trades.
I might as well restate my feeling that this is less a reaction to fears of false alarms, than it is an attempt to head off independent investigations, like those that undermined the NYC/EPA "party line" concerning air quality after the 9/11 attacks.
Thoriated filaments were generally only used in early receiving tubes, and high-power transmitting tubes. They would probably be the easiest way to manufacture a usable tube in your basement, but they weren't general industry practice for audio tubes.
Most audio/receiving types used either an oxide coated filament, or a separate, indirectly heated cathode. The filament/cathode was coated with a mixture of barium/strontium/calcium carbonates, which converted to the corresponding oxides during the heating and pumpdown process. The oxide layer emitted electrons at an even lower temperature than thoriated tungsten.
The article talks at great length about the manufacture of the CRT bulbs, and the exhaust process, both of which were easily automated, even back then. I talked about the automated "sealex" machines in my last post.
But the heart of the CRT, the electron gun, with it's tiny metal components, was still hand assembled, by operators using microscopes and tiny resistance spot welders. Just the same as standard receiving tubes. The final assembly and evacuation lent itself to automation, but the intricate assembly of the "guts" did not.
Vacuum tubes were pretty much ALL hand-made....
on
Hand-Made Vacuum Tubes
·
· Score: 4, Interesting
, as sophisticated robotics didn't yet exist. The most sophisticated part of tube making, the assembly of the internal components or "mount" was done largely by hand, usually by rows and rows of women (smaller fingers) hunched over microscopes in dust-free rooms.
Once the mounts were assembled and welded onto the stems, the sealing into bulb and pumping down was somewhat automated. Done on a machine called a "sealex", the mounts would be inserted into bulbs, sealed in place, evacuated, heated to activate the cathodes, sealed off, and getters flashed, with each operation taking place at a different "station" on the sealex.
An interesting photo essay on the construction of the famous 300B audio triode is available here:
He was superheating the entire structure to drive out occluded gases from the metal components. During this operation, the entire tube was surrounded by a coil driven by an induction heater, which was heating the plate and grid red hot, as well. All this takes place while the tube is attached to the vacuum pump, prior to sealoff.
I am not sure what material he was using for his filament wire, but if it was thoriated tungsten, then the "hot shot" cycle also serves to build up a surface layer of thorium oxide on the filament, and reduce it to metallic thorium. Thorium has a much lower work function than pure tungsten, and will emit electrons efficiently at a much lower operating temperature.
Yes, I am a tube geek...:) Years ago, I made a much cruder triode in a peanut butter jar as a HS physics project.
Semiconductors never could have been made without
on
Hand-Made Vacuum Tubes
·
· Score: 4, Informative
vacuum tubes.
Once you get beyond the crude PN junction diode (like a galena crystal), making transistors and such requires ridiculously pure germanium and/or silicon. These materials are purified by a process called "zone refining" which uses induction heating to melt the semiconductor materials at incredibly high temperatures. Induction heating in turn requires many kilowatts of radio frequency power, which is exactly the type of application where vacuum tubes are still widely used even today.
If you look closely at the wires he is sealing into the glass "press", you will see a short reddish-brown section. This is most likely "dumet", or copper coated nickel/iron. This material is specially designed to have the same coefficient of thermal expansion as glass, and was used as the sealing material in most receiving tubes. The copper coating forms an oxide layer that dissolves into the glass, creating a vacuum-tight seal.
Before the development of dumet, kovar, and other specialized alloys, the seals in very early tubes were made using platinum wire. Cost considerations brought this to a quick end, as soon as cheaper suitable materials were developed.
The electrodes in later tubes were often coated with various materials to aid heat dissipation or reduce secondary electron emission. Early tubes that were similar in construction to what is being made here generally used plain metal grids and plates.
Most tubes contained a "getter" made of barium or other reactive metal, to adsorb any gas molecules which survived initial pumpdown, or which were liberated from the internal elements during operation.
Slashdot Mirror
and memory cards. Users of the last generation of industrial control equipment come to mind immediately. I maintain a couple of industrial touchscreen interface panels that store configuration setups on CF cards, but cannot support CF cards larger than 128 MB due to firmware limitations.
This is industrial strength hardware that that would take serious $$$ to replace, a lot of time to migrate the software and debug the interface for, and it is perfectly functional. The only problem is that the mass-market applications for flash memory (digital cameras and music players) have long since outgrown the 16 or 32 MB cards that are used to store machine setups. So memory card manufacturers no longer manufacture the smaller sizes, because the market is so limited. So users either have the choice of paying $$$ for obsolete memory cards from automation suppliers, or buying them (often for less than the shipping cost) on eBay.
, they are relatively "clean", and employ lots of white collar/upper middle class workers. Most communities were glad to have them built nearby. Especially, when they were helping "beat those commies to the moon".
A heavy steel forging operation, OTOH, would face opposition because of the smokestack emissions, and the ingrained idea that we don't need workers who actually MAKE anything anymore, when we can base our entire economy on shuffling money around and suing each other.
It wasn't just for vibration damping.
The heating caused by the electron beams hitting the aperture grille would cause the grill wires to expand slightly. If they weren't mechanically fastened together, the grille would warp out of shape enough to cause problems with convergence and purity.
http://en.wikipedia.org/wiki/Briggs-Rauscher_reaction
, because hobby chemistry was pretty much destroyed well before 9/11. The "War on Drugs" caused most chemical sellers to eliminate sales to individuals, and in some states (like Texas) it is illegal to even own laboratory glassware without a permit (and regular inspections) from local police.
Add in the effect of lawyers and insurance companies (who drove chemistry sets off of toy store shelves), and you have one more "perfect storm" contributing to the ongoing "dumbing down" of the US.
First off, NOTHING is going to prevent serious damage in the case of a direct lightning strike onto the electrical wires feeding your house. The energy levels involved are far beyond what any type of household surge suppressor is going to handle.
The problem with installing surge suppression at the outlet is that the surge current being dumped into the far end of a grounded wire will simply cause the voltage on that end of the conductor to spike upwards, due to the conductor's resistance, and more importantly in the case of a fast risetime transient, the wire's inductance.
You now have the grounded case of the computer system or whatever you were trying to protect elevated hundreds or thousands of volta above earth ground. This voltage then looks for alternate paths to ground via ethernet cables, phone lines, or anything else plugged into it.
In fact, these type of devices can often provide a false sense of security for the user.
In order for a surge protector to function effectively, it needs a short. low impedance path to the building's main electrical service ground. Devices that plug in at the receptacle are connected to ground only through the branch circuit wiring, which may be a hundreds feet of more in length before it gets back to the main electrical panel. All that wire length adds resistance and inductance, which can completely negate the effectiveness of the surge protector. The situation is even worse in older buildings, where the receptacle ground may not even be copper wire, but the galvanized steel spiral armor on "BX" type cable.
The only surge protection that is worth a damn is installed (hard wired, by a qualified person) at the main building electrical panel, where the diverted energy can be dumped directly into the main building ground with a heavy gauge conductor. These type of units protect ALL the wiring in the building, rather than just selected receptacles.
Wall warts also allow product designers to accommodate regional variations in voltage/frequency/receptacle format by simply shipping the appropriate wallwart for the destination country. Avoids the problems with different power transformers, fuses, and cordsets for different countries.
That way, if the grid went down, there would be SOMEWHERE to dump the output of the alternator, at least until the plant can be shut down in a controlled manner.
Large backup generator installations have load banks installed so that the generator can be tested under load on a regular basis, without actually having to cut the facility power off of the grid.
"Bernie Sanders was supposedly further left than whole damn Green Party combined"
According to who? Sanders has been a bit of a disappointment, but then again, so has the rest of the Congress.
Bernie Sanders isn't even the farthest to the left in the US Congress (that would seem to be Dennis Kucinich). Kucinich really should consider jumping ship and joining the Greens, like Cynthia McKinney did. The Democratic Party machine is supporting several challengers to his congressional seat, probably as payback for being too vocal about impeachment and the various Bush regime atrocities.
Similar piece of hardware, but larger/higher powered.
Vibrators were used in vacuum tube car radios and other applications where high voltages were needed and only low voltage DC power was available. The vibrator was essentially a buzzer that was used to rapidly switch DC power on and off in the primary of a transformer, creating a pulsating DC which could be stepped up by the transformer and then rectified/filtered and used as the plate voltage for the vacuum tubes. They were constant trouble sources, with contacts that would stick (and blow the radio fuse), and they emitted large amounts of RF noise which had to be filtered out for the rest of the radio to work. Sometimes they wouldn't want to start without pounding the dashboard to get the weighted reed inside moving.
They were rendered obsolete once crude power transistors came along, allowing the audio power output stage of a car radio to be transistorized. The other stages of the radio could then use specially designed tubes that would operate at low voltages, or, in a few short years, they became fully solid state.
The electromechanical choppers that were used to stabilize op-amps in precision instrumentation were somewhat similar devices, but they tended to be more reliable because they only switched tiny signal levels, as opposed to the 15-20A typical of a car radio operated from the then standard 6 volt battery.
Toad licks YOU!
about the hydrazine fuel onboard, and the hazard it would pose to anyone on the ground, as if the fuel tanks would survive the breakup and atmospheric heating of the re-entry.
Looks like a great chance for the Bush regime to pull off an ASAT test, with a ready-made cover story to deflect blame for all the space junk it will create.
But being carbon compounds, hydrocarbons are, by definition, ORGANIC molecules.
do electrical work on a building that they personally live in. If you own a building which you rent out, you are required to use a licensed electrician. Ditto for a building used for a business or other non-residential purposes. I believe the same goes for plumbing and other licensed trades.
I might as well restate my feeling that this is less a reaction to fears of false alarms, than it is an attempt to head off independent investigations, like those that undermined the NYC/EPA "party line" concerning air quality after the 9/11 attacks.
http://www.rugglesmine.com/
I have dug a few hot rocks out of there, as well.
, cause that sucker is going down in flames....
in that an LP jacket is large enough to use as a work surface for cleaning your weed and rolling a joint.
A CD jewel box is way too small, and don't get me started on MP3s...:)
Thoriated filaments were generally only used in early receiving tubes, and high-power transmitting tubes. They would probably be the easiest way to manufacture a usable tube in your basement, but they weren't general industry practice for audio tubes.
Most audio/receiving types used either an oxide coated filament, or a separate, indirectly heated cathode. The filament/cathode was coated with a mixture of barium/strontium/calcium carbonates, which converted to the corresponding oxides during the heating and pumpdown process. The oxide layer emitted electrons at an even lower temperature than thoriated tungsten.
The article talks at great length about the manufacture of the CRT bulbs, and the exhaust process, both of which were easily automated, even back then. I talked about the automated "sealex" machines in my last post.
But the heart of the CRT, the electron gun, with it's tiny metal components, was still hand assembled, by operators using microscopes and tiny resistance spot welders. Just the same as standard receiving tubes. The final assembly and evacuation lent itself to automation, but the intricate assembly of the "guts" did not.
, as sophisticated robotics didn't yet exist. The most sophisticated part of tube making, the assembly of the internal components or "mount" was done largely by hand, usually by rows and rows of women (smaller fingers) hunched over microscopes in dust-free rooms.
Once the mounts were assembled and welded onto the stems, the sealing into bulb and pumping down was somewhat automated. Done on a machine called a "sealex", the mounts would be inserted into bulbs, sealed in place, evacuated, heated to activate the cathodes, sealed off, and getters flashed, with each operation taking place at a different "station" on the sealex.
An interesting photo essay on the construction of the famous 300B audio triode is available here:
http://www.westernelectric.com/history/tour01.html
He was superheating the entire structure to drive out occluded gases from the metal components. During this operation, the entire tube was surrounded by a coil driven by an induction heater, which was heating the plate and grid red hot, as well. All this takes place while the tube is attached to the vacuum pump, prior to sealoff.
I am not sure what material he was using for his filament wire, but if it was thoriated tungsten, then the "hot shot" cycle also serves to build up a surface layer of thorium oxide on the filament, and reduce it to metallic thorium. Thorium has a much lower work function than pure tungsten, and will emit electrons efficiently at a much lower operating temperature.
Yes, I am a tube geek...:) Years ago, I made a much cruder triode in a peanut butter jar as a HS physics project.
vacuum tubes.
Once you get beyond the crude PN junction diode (like a galena crystal), making transistors and such requires ridiculously pure germanium and/or silicon. These materials are purified by a process called "zone refining" which uses induction heating to melt the semiconductor materials at incredibly high temperatures. Induction heating in turn requires many kilowatts of radio frequency power, which is exactly the type of application where vacuum tubes are still widely used even today.
If you look closely at the wires he is sealing into the glass "press", you will see a short reddish-brown section. This is most likely "dumet", or copper coated nickel/iron. This material is specially designed to have the same coefficient of thermal expansion as glass, and was used as the sealing material in most receiving tubes. The copper coating forms an oxide layer that dissolves into the glass, creating a vacuum-tight seal.
Before the development of dumet, kovar, and other specialized alloys, the seals in very early tubes were made using platinum wire. Cost considerations brought this to a quick end, as soon as cheaper suitable materials were developed.
The electrodes in later tubes were often coated with various materials to aid heat dissipation or reduce secondary electron emission. Early tubes that were similar in construction to what is being made here generally used plain metal grids and plates.
Most tubes contained a "getter" made of barium or other reactive metal, to adsorb any gas molecules which survived initial pumpdown, or which were liberated from the internal elements during operation.