I like in England, where we're mostly metric (although a lot of Imperial units are still used), but ALL scientists use metric for everything. It's not because of some magical superiorty science that normal people need either, it's mostly because multiplying by 10 is a lot easier than multiplying by 12 then 16 then 8, or whatever!
I do all of my physics using the metric system and most of my mechanical engineering using imperial units. In my ideal world, we combine Newton's advocacy for base 12 math with the French measurement system yielding the best of both worlds: dimensional analysis without conversion constants and evenly divisible fractions other then 2 and 5.
Unfortunately, Heathkit is long gone as their instruction manuals contained excellent tutorials on circuit construction and operation. Radio Electronics magazine is no more but Circuit Cellar magazine is still going and tends to be more computer and interface oriented anyway. I do not remember the name but there was a European magazine called something like "Electronics" that might have been "EPE" that was also very good. For whatever reason, the Europeans always seemed more hands on then the Americans. If you are inclined toward radio then getting your amateur radio license and subscribing to the ARRL's QST magazine and possibly their much more technical QEX magazine is a sure way to start learning.
Don Lancaster and Bob Pease have authored books on electronics design and construction that have lessons for beginners through degreed engineers. The various Linear Technology application books are also very good with special emphasis on the ones written by Jim Williams.
The one piece of equipment that beginners tend to overlook is the soldering iron. Temperature controlled pencil irons are available for about $100 that are worth every penny. I especially like the old style Weller Magnastat designs which are currently listed as the WTCPT series.
If you can stand paying a little more, small embedded x86 routers are available for just under $200 new that can use either m0n0wall or pfsense which are php/xml based web front ends that run on FreeBSD. m0n0wall currently does not support OpenVPN but there is a slightly older version 1.21 image available that has it compiled in. Both fully support IPSEC and have PPPoE and PPTP servers. If you need more then 5 Mbit/s VPN performance or 30 Mbit/s router performance then there are slightly larger boxes available which can scale up to handle anything you will likely need. There are general PC versions of both packages that you can use to do testing on an available PC to see if either would meet your needs.
Film capacitors use either a metal foil separated by a film dielectric or a deposited metal film on the film dielectric itself which yields higher volumetric efficiency at the expense of series resistance. The plastic films that can be used include polycarbonate, polyester/mylar, polystyrene, polypropylene, and teflon depending on the application. Polyester are the most common but has a poor temperature coefficient and poor dielectric absorption compared to the others. Polystyrene probably has the best price to performance but can not be exposed to temperatures above about 85C because the polystyrene will undergo a phase change.
Very large film capacitors are now available as aluminum electrolytic replacements in motor start and audio applications.
At least with the early ones the equivalent series resistance was relatively high making them completely unsuitable for filtering applications. The newer ones are better in this respect but still do not compete with other capacitor technologies except where very high capacitance is required and the relatively large ESR can be tolerated. Keep in mind that while Energy = 1/2 CV^2, capacitor volume is proportional to CV. If you really want a scary discharge use a high voltage film or electrolytic capacitor.
If he had placed the pump on the outgoing side all of the water block connections would have been at negative pressure preventing water leakage where it would do the most damage. Swimming pool plumbing tends to be made of copper alloys like bronze so I doubt corrosion will be a problem as long as he sticks with copper.
How does the capacity of a drive have anything to do with its seek time? Seek time is a function of how quickly the read arm can cross the radius of the platter, and to a smaller degree how fast the platter spins. The article claims they will be increasing storage density using this HARM thing so that more bits can be stored on the same amount of surface area. Seek time should not change significantly unless they make the platters larger, or spin the drive at lower RPM.
For a given amount of data and drives with the same physical dimensions, doubling the track density will halve the seek time excluding other factors like settling time which will become slightly worse. Track density probably goes up at about 1.4 times the areal density. Another way to look at it is that the data takes up less space on the disk so the heads do not have to move as far to reach it. None of this affects the rotational latency which adds to the access time.
Back when seek time was a majority of the access time, switching to a higher capacity drive made for significant improvements in performance. These days the seek time and the rotational latency are about equal so higher density drives are only marginally faster.
The TDMA used by GSM is a form of AM modulation and can be detected by a PN junction or other non-linear circuit. Audio amplifier input circuits are normally shielded or filtered to prevent this but the power levels involved in a transmitter also make output circuits susceptible.
"Linear" in this case refers to an 11 meter power RF amplifier with a linear transfer characteristic which is required to amplify AM or SSB signals without distortion.
Probably beryllium copper which has characteristics not unlike steel and is tougher then bronze. Brass works well for non marring hammers but would be too soft for many applications.
I wonder how the TSA security screeners handle this. I have the vision of a traveller picking up their luggage and discovering all of their christmas gifts destroyed so that TSA could check them for explosives with a little note left behind saying, "Nothing found. TSA."
. . . op-amps produce odd harmonics in their reproduction.
I would hope their amplifier design produces so little distortion that it is not even close to audible under normal operating conditions.
Even harmonics are soothing and odd harmonics are grating. THAT is what "warmer" means. You can disguise the odd harmonics by adding more but a tube amp doesn't have to so it doesn't have to work as hard to get the same quality of sound. That is why tube amps sound louder than their wattge (3x approximately).
I remember an analysis of east coast versus west coast speakers that showed the warmer sounding east coast ones simply had a different equalization which emphasized the middle frequency range but I never saw any distortion measurements which could also have figured into the differences. The odd harmonic distortion that transistor amplifiers are prone to is certainly harsh and I always worked to remove it rather then add even harmonic distortion.
I have tended to associate the effect of sounding loud without being indistinct to low intermodulation distortion but distinguishing that from even and odd harmonic distortion is not easy without careful measurement. In modern amplifier designs the speakers should be the limiting factor. I fondly remember the first time watching Aliens at home and listening to the drop ship sequence on 4 critically damped bass reflex speakers that had been individually tuned. After being exposed to systems that suffer from lots of intermodulation distortion creating the popular big boom sound, it was almost odd to have to limit the volume to prevent the windows from rattling and breaking. It was simultaneously loud while being easy to listen to.
And non-class A amps rectify and amplify the signal separately positivey and negatively, so there is a small error in the evenness of the positivve and negative waveform.
For small signal and headphone amplifiers based on op-amps there are a couple of easy things that can be done to switch their class AB output stages into single ended class A mode albeit with the associated penalties in efficiency and output power. This really should only be a problem with improperly specified op-amps.
Operating an RF transmitter in proximity to an audio amplifier without creating audible artifacts is a non trivial engineering exercise. Not only do you have to worry about the obvious sources of interference through the input and power supply lines but the output stages can be affected through the output leads. Usually the interference mechanism is AM rectification by PN junctions. The WiFi signal itself is probably not the problem but turning the transmitter on and off is a form of AM modulation. Cellular phones using TDMA have the same issues.
As near as I was able to find out, 1T-SRAM is standard single capacitor single transistor dynamic RAM technology optimised for a logic process and using masked refresh.
The sacking of Hobbiton kind of works as a smaller "unwinding story" at the end of the book, but it would probably feel even more like dragging on the ending if they put it in the movie. It's also too much of a cliché already for heroes to return from a successful quest to a wrecked home village (though perhaps that could have left room for a sequel).
It is not so much the sacking of Hobbiton but the changes in Frodo, Sam, Merry, and Pippin that were displayed in The Scouring of the Shire. As it is they return, Frodo leaves in pain with the elves, and the rest live happily ever after drinking beer at the Green Dragon with little to show for participating in the war of the ring. In the book, Merry and Pippin return having the stature if not the height, although Treebeard's gift foreshadows their new character, of the warriors of Gondor and Rohan ready to be led into battle by Frodo and Sam who themselves are fierce in the way of hobbits of legend. They all retain only an echo of their timid former selves.
To be fair, I would never claim to be unbiased. The Scouring of the Shire reminds me of the battle that took place in Athens, Tennessee after World War Two and I have often wondered if despite Tolkien's dislike for allegory he was thinking of some similar event in England after World War One.
The frequency division multiplexing used to divide the receive and transmit signals is easier to implement then the echo cancellation necessary when your transmit and receive bands are the same. If you are going to separate your transmit and receive spectrums, you might as well tailor them for the most common usage which is large downloads and small uploads.
As much as I dislike Sony, I can not fault them for this since it is established practice in the machining industry. Milling machines use the term axis for both translation and rotation so when one speaks of a 5 axis milling machine it would generally include X, Y, Z, and 2 other rotations like workpiece rotation and tool tilt.
I say limit the amount of ads a politician can have. I say 2 TV ads and that's it . ..
Not that it would pass constitutional muster but I often wonder what the effect would be to forgo television and radio completely and limit political debate and advertisement to writing including newspapers, literature, blogs, usenet, and whatnot. You could not restrict public discussion so maybe only limit prerecorded audio and visual media while allowing live broadcasts and their recordings. My hypothesis is that because of the differences in the way speech and writing are learned and processed in the brain, political discourse would be more rational then emotional.
A majority of x86 PCs still use processors that do not support x86-64 and even now x64-32 processors are still manufactured and in the sales channel. Without a 32 bit version of Vista, not only would these older systems be left without a Windows upgrade earlier then neccessary but both these systems and some applications would be lost to alternative non Windows operating systems.
I would not expect the antenna and associated electronics to survive more then a fraction of a second in a microwave. If it has overload or ESD protection, that is the first thing that would be destroyed. The magetic stripe would heat up but should survive until the plastic or binder melts.
Continental Europe is different - they're a bit more strict on privacy laws. There's always a big stink made when some stuff like this happens, like when euro passenger data is shared with the US, or like when SWIFT Belgium was/is passing loads of info on financial transactions to the US (again).
Perhapse having a more direct experience with occupation under World War II Germany makes continental Europe more leary of these types of social restrictions.
Slashdot Mirror
I like in England, where we're mostly metric (although a lot of Imperial units are still used), but ALL scientists use metric for everything. It's not because of some magical superiorty science that normal people need either, it's mostly because multiplying by 10 is a lot easier than multiplying by 12 then 16 then 8, or whatever!
I do all of my physics using the metric system and most of my mechanical engineering using imperial units. In my ideal world, we combine Newton's advocacy for base 12 math with the French measurement system yielding the best of both worlds: dimensional analysis without conversion constants and evenly divisible fractions other then 2 and 5.
Unfortunately, Heathkit is long gone as their instruction manuals contained excellent tutorials on circuit construction and operation. Radio Electronics magazine is no more but Circuit Cellar magazine is still going and tends to be more computer and interface oriented anyway. I do not remember the name but there was a European magazine called something like "Electronics" that might have been "EPE" that was also very good. For whatever reason, the Europeans always seemed more hands on then the Americans. If you are inclined toward radio then getting your amateur radio license and subscribing to the ARRL's QST magazine and possibly their much more technical QEX magazine is a sure way to start learning.
Don Lancaster and Bob Pease have authored books on electronics design and construction that have lessons for beginners through degreed engineers. The various Linear Technology application books are also very good with special emphasis on the ones written by Jim Williams.
The one piece of equipment that beginners tend to overlook is the soldering iron. Temperature controlled pencil irons are available for about $100 that are worth every penny. I especially like the old style Weller Magnastat designs which are currently listed as the WTCPT series.
If you can stand paying a little more, small embedded x86 routers are available for just under $200 new that can use either m0n0wall or pfsense which are php/xml based web front ends that run on FreeBSD. m0n0wall currently does not support OpenVPN but there is a slightly older version 1.21 image available that has it compiled in. Both fully support IPSEC and have PPPoE and PPTP servers. If you need more then 5 Mbit/s VPN performance or 30 Mbit/s router performance then there are slightly larger boxes available which can scale up to handle anything you will likely need. There are general PC versions of both packages that you can use to do testing on an available PC to see if either would meet your needs.
Firstly, WTF are film/foil capacitors?
Film capacitors use either a metal foil separated by a film dielectric or a deposited metal film on the film dielectric itself which yields higher volumetric efficiency at the expense of series resistance. The plastic films that can be used include polycarbonate, polyester/mylar, polystyrene, polypropylene, and teflon depending on the application. Polyester are the most common but has a poor temperature coefficient and poor dielectric absorption compared to the others. Polystyrene probably has the best price to performance but can not be exposed to temperatures above about 85C because the polystyrene will undergo a phase change.
Very large film capacitors are now available as aluminum electrolytic replacements in motor start and audio applications.
At least with the early ones the equivalent series resistance was relatively high making them completely unsuitable for filtering applications. The newer ones are better in this respect but still do not compete with other capacitor technologies except where very high capacitance is required and the relatively large ESR can be tolerated. Keep in mind that while Energy = 1/2 CV^2, capacitor volume is proportional to CV. If you really want a scary discharge use a high voltage film or electrolytic capacitor.
If he had placed the pump on the outgoing side all of the water block connections would have been at negative pressure preventing water leakage where it would do the most damage. Swimming pool plumbing tends to be made of copper alloys like bronze so I doubt corrosion will be a problem as long as he sticks with copper.
How does the capacity of a drive have anything to do with its seek time? Seek time is a function of how quickly the read arm can cross the radius of the platter, and to a smaller degree how fast the platter spins. The article claims they will be increasing storage density using this HARM thing so that more bits can be stored on the same amount of surface area. Seek time should not change significantly unless they make the platters larger, or spin the drive at lower RPM.
For a given amount of data and drives with the same physical dimensions, doubling the track density will halve the seek time excluding other factors like settling time which will become slightly worse. Track density probably goes up at about 1.4 times the areal density. Another way to look at it is that the data takes up less space on the disk so the heads do not have to move as far to reach it. None of this affects the rotational latency which adds to the access time.
Back when seek time was a majority of the access time, switching to a higher capacity drive made for significant improvements in performance. These days the seek time and the rotational latency are about equal so higher density drives are only marginally faster.
The 8088 with its 8 bit external data bus allowed the use of existing 8080 peripheral chips. The Motorola 68008 was not released until later.
The TDMA used by GSM is a form of AM modulation and can be detected by a PN junction or other non-linear circuit. Audio amplifier input circuits are normally shielded or filtered to prevent this but the power levels involved in a transmitter also make output circuits susceptible.
"Linear" in this case refers to an 11 meter power RF amplifier with a linear transfer characteristic which is required to amplify AM or SSB signals without distortion.
Probably beryllium copper which has characteristics not unlike steel and is tougher then bronze. Brass works well for non marring hammers but would be too soft for many applications.
I wonder how the TSA security screeners handle this. I have the vision of a traveller picking up their luggage and discovering all of their christmas gifts destroyed so that TSA could check them for explosives with a little note left behind saying, "Nothing found. TSA."
. . . op-amps produce odd harmonics in their reproduction.
I would hope their amplifier design produces so little distortion that it is not even close to audible under normal operating conditions.
Even harmonics are soothing and odd harmonics are grating. THAT is what "warmer" means. You can disguise the odd harmonics by adding more but a tube amp doesn't have to so it doesn't have to work as hard to get the same quality of sound. That is why tube amps sound louder than their wattge (3x approximately).
I remember an analysis of east coast versus west coast speakers that showed the warmer sounding east coast ones simply had a different equalization which emphasized the middle frequency range but I never saw any distortion measurements which could also have figured into the differences. The odd harmonic distortion that transistor amplifiers are prone to is certainly harsh and I always worked to remove it rather then add even harmonic distortion.
I have tended to associate the effect of sounding loud without being indistinct to low intermodulation distortion but distinguishing that from even and odd harmonic distortion is not easy without careful measurement. In modern amplifier designs the speakers should be the limiting factor. I fondly remember the first time watching Aliens at home and listening to the drop ship sequence on 4 critically damped bass reflex speakers that had been individually tuned. After being exposed to systems that suffer from lots of intermodulation distortion creating the popular big boom sound, it was almost odd to have to limit the volume to prevent the windows from rattling and breaking. It was simultaneously loud while being easy to listen to.
And non-class A amps rectify and amplify the signal separately positivey and negatively, so there is a small error in the evenness of the positivve and negative waveform.
For small signal and headphone amplifiers based on op-amps there are a couple of easy things that can be done to switch their class AB output stages into single ended class A mode albeit with the associated penalties in efficiency and output power. This really should only be a problem with improperly specified op-amps.
Operating an RF transmitter in proximity to an audio amplifier without creating audible artifacts is a non trivial engineering exercise. Not only do you have to worry about the obvious sources of interference through the input and power supply lines but the output stages can be affected through the output leads. Usually the interference mechanism is AM rectification by PN junctions. The WiFi signal itself is probably not the problem but turning the transmitter on and off is a form of AM modulation. Cellular phones using TDMA have the same issues.
As near as I was able to find out, 1T-SRAM is standard single capacitor single transistor dynamic RAM technology optimised for a logic process and using masked refresh.
The sacking of Hobbiton kind of works as a smaller "unwinding story" at the end of the book, but it would probably feel even more like dragging on the ending if they put it in the movie. It's also too much of a cliché already for heroes to return from a successful quest to a wrecked home village (though perhaps that could have left room for a sequel).
It is not so much the sacking of Hobbiton but the changes in Frodo, Sam, Merry, and Pippin that were displayed in The Scouring of the Shire. As it is they return, Frodo leaves in pain with the elves, and the rest live happily ever after drinking beer at the Green Dragon with little to show for participating in the war of the ring. In the book, Merry and Pippin return having the stature if not the height, although Treebeard's gift foreshadows their new character, of the warriors of Gondor and Rohan ready to be led into battle by Frodo and Sam who themselves are fierce in the way of hobbits of legend. They all retain only an echo of their timid former selves.
To be fair, I would never claim to be unbiased. The Scouring of the Shire reminds me of the battle that took place in Athens, Tennessee after World War Two and I have often wondered if despite Tolkien's dislike for allegory he was thinking of some similar event in England after World War One.
The frequency division multiplexing used to divide the receive and transmit signals is easier to implement then the echo cancellation necessary when your transmit and receive bands are the same. If you are going to separate your transmit and receive spectrums, you might as well tailor them for the most common usage which is large downloads and small uploads.
Luckily, my house has stairs, so they'll be stuck milling around outside in their wheelchairs when they come to get me.
If this is the extend of your defenses than I hope the Daleks are not involved.
As much as I dislike Sony, I can not fault them for this since it is established practice in the machining industry. Milling machines use the term axis for both translation and rotation so when one speaks of a 5 axis milling machine it would generally include X, Y, Z, and 2 other rotations like workpiece rotation and tool tilt.
Remember that this is the FBI we are talking about. There would be no point in burning him out unless he was home.
I say limit the amount of ads a politician can have. I say 2 TV ads and that's it . . .
Not that it would pass constitutional muster but I often wonder what the effect would be to forgo television and radio completely and limit political debate and advertisement to writing including newspapers, literature, blogs, usenet, and whatnot. You could not restrict public discussion so maybe only limit prerecorded audio and visual media while allowing live broadcasts and their recordings. My hypothesis is that because of the differences in the way speech and writing are learned and processed in the brain, political discourse would be more rational then emotional.
A majority of x86 PCs still use processors that do not support x86-64 and even now x64-32 processors are still manufactured and in the sales channel. Without a 32 bit version of Vista, not only would these older systems be left without a Windows upgrade earlier then neccessary but both these systems and some applications would be lost to alternative non Windows operating systems.
I would not expect the antenna and associated electronics to survive more then a fraction of a second in a microwave. If it has overload or ESD protection, that is the first thing that would be destroyed. The magetic stripe would heat up but should survive until the plastic or binder melts.
. . . Maybe it's an Anglo-Saxon mindset?
Continental Europe is different - they're a bit more strict on privacy laws. There's always a big stink made when some stuff like this happens, like when euro passenger data is shared with the US, or like when SWIFT Belgium was/is passing loads of info on financial transactions to the US (again).
Perhapse having a more direct experience with occupation under World War II Germany makes continental Europe more leary of these types of social restrictions.
Most though not all current embedded hardware used for m0n0wall that can be had for about $200 meets the pfsense embedded requirements.