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    question about speakers and phase

    If you reverse the polarity of one speaker in a standard two speaker stereo system that is set up to produce stereo, you will definitely notice the difference. At the mid point between the two speakers, it will sound sort of dead. As you move to either side, you will hear the closer speaker to...
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    So I've always wondered where molecular energy comes from...

    This is a first law of thermodynamics situation. Writing heat flow, Q, in as +, and work done, W, by the water/ice as +, the first law is Q = W + delta U, where delta U is the change in internal energy. Since heat flows out as the water freezes (so Q is -) it's not the heat flow that does the...
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    Complex Fourier transforms and Quadrature detection

    There must be someone more on top of this than I am, but you should be basically OK. Your system is essentially what's used in a TV or radio - an f-fr signal is produced over a frequency range convenient for processing. The final spectrum analysis is done by ear (for a radio) and the spectrum...
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    Need help with a Heat Load Study

    For a first estimate for the knds of devices you mention, all of the energy could be taken as showing up as heat sooner or later. In most cases, the energy in goes pretty directly to heat - thermodynamically a PC just sits there and makes heat. Even the spinning disk, fan etc energy ends up as...
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    Why does AM radio suck so bad???

    There are a couple of issues here. As has been pointed out, a lot of the power line noise has to do with the type of detection used in AM. Most of the noise appears as amplitude variations, so an AM radio is likely to detect it. FM detection if perfect does not notice amplitude variations...
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    Help Defining a Wave

    Sillverpig's definition is pretty good. A wave is the solution to a wave equation (classical or quantum mechanical).
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    Geiger counters

    That does make sense. The lighter particles in the stronger field would seem to make for a sharper edge on a bigger pulse. Maybe that's it. A long time ago, I worked with someone who was a great fan of GM detectors, and I know he explained more than just the basic operation. But, I've...
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    Geiger counters

    Good question. It doesn't seem as if it would make any difference - you would get a discharge in the gas when it was ionized with either polarity. Maybe it has something to do with the detector connections. GM tubes have been around for many decades. It could be it was once easier (and maybe...
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    Wireless power transmission

    An AC carrying inductor placed near the steel plate will induce eddy currents in the plate (because it's a conductor). You will probably end up using quite a bit of your power in just heating up the plate with the eddy currents. As others have said, it really seems as if you should be trying...
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    Radio Question

    Any nonlinear element in a circuit can cause an unintentional detection of a strong radio signal. The speaker wirew, power cord, audio input cables (even if shielded) etc. can serve as an antenna bringing RF into your amp. If this RF voltage is big enough, iit can drive something out of its...
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    how fast does a space station have to spin to generate gravity?

    Well - It's a pretty round number and I didn't have a calculator within reach.
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    how fast does a space station have to spin to generate gravity?

    It depends on the size. The centripetal acceleration is v^2/r at a distance r from the center of rotation. For example, to get 1 g at 100 meters, you would have to go about 30 m/s. That would amount to about 3 rpm!
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    Sound-upon-sound question

    Multiple sources of sound just add. What actually adds is the sound waves, the total wave amplitude at any time and location being the sum of all the waves. Usually, such as with the vacuum cleaner and TV, the sources have no defininite phase relationship, and you can just add the intensities...
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    200+amps on 12v

    This is a lot of power - 2400 watts. Even at 100% efficiency, this translates to 20 A at 120 volts. So, when you get it done, you will need a 30 A circuit to run it. Starting from 240 VAC might be a better option. DC power supplies in this range are possible, but it might cost a few bucks...
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    pc133 ram.. ?

    Should be OK. I think I have that in an old celeron based computer. The PC133 will just run at PC100 speed.
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    I need a replacement potentiometer for my logitech z-2200 controller.

    You could try Mouser (www.mouser.com). It will take a while to wade through all the possibilities, but they do carry alpha and you can just keep looking until you find a matching picture. You are probably looking for a 10K ohm pot. Chances are good that you want an audio taper (the other...
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    Broadband through power lines...

    I wish what you say were true, but that's exactly what one form of BPL means, and I think that's what OP was referring to. Using existing towers, etc to support sheilder or fiber cable wouldn't cause anyone any trouble, but the several pilot programs that ran recently and may still be in...
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    Broadband through power lines...

    Harrkev - I also doubt it, but had read that Bendix was going to try a different system that showed promise compared to the Amperion hardware that didn't work. My personal opinion is that this is not a good way to extend broadband to remote regions for exactly the reasons you said. It is hard...
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    Broadband through power lines...

    Inhome broadband over house wiring is not the source of the spectrum pollution problem. It's the access BPL signals that have caused trouble in most of the pilot programs (many of which have been discontinued for a variety of reasons). Access BPL works by inductively coupling a data signal to...
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    Broadband through power lines...

    I agree with harrkev. The danger to your system from a power surge or to you from electrocution with BPL is probably no greater than it already is without BPL because you use electricity from the power company. The real problem is spectrum pollution. There have been several pilot BPL...
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    Question on Astronomy

    Do a search on "Hubble Constant" and you will probably find as much information as you could want on determining astronomical distances.
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    Why can't matter reach the speed of light?

    A photon is light. Not surprisingly, it travels at the speed of light. Photons don't start from rest and accelerate.
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    WiFi Signal Level Fluctuating

    A 60% change in power is a little over 2 dB. That sounds within normal behavior.
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    50hz clock ** Update **

    You can power your circuit from a 9 volt wall wart supply. The current rating only has to be comfortably more than your circuit uses. The circuit will just draw what it needs - not the whole 1.5 A. Sometimes those power supplies produce DC that's not real clean, and this can cause trouble...
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    What was your first Computer?

    Mine was a VIC 20 too. It's still around somewhere, but the cassette quit years ago.
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    Power Consumption

    Also, you measure the power in watts. You would measure the total energy used in Kilowatt hours (KWH) which is what the electric company charges you for. KWH is just what it says - the KW times the time in hours.
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    Understanding DC current from battery source...

    The electrons do indeed flow from the negative side of the battery through the external circuit (engine block, etc.) and back into the positive side. For historical reasons, electric current is thought of as a flow of positive charge the other way. For almost every situation, it doesn't matter...
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    what SPECS determine good sound quality?

    SNR means signal to noise ratio. Bigger is better, and it probably comes in dB, but I don't remember what numbers to look for. It's my impression that most modern sound equipment is very satisfactory in this department. THD is total harmonic distortion and will usually be given as a...
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    Grounding a wooden computer case

    One of the functions of the grounded metal case is to reduce rf radiation from the computer. I had a 486 system that interfered with a non-cable TV located about 5 feet away, so the problem can be real. However, it seems as if newer systems don't have as much problem in this regard. If you...
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    audio sampling rate

    I'll give a quick stab here. There are undoubtedly those who know more. When an analogsignal is digitized, the voltage is measured a bunch of times per second and each measurement is stored as a number. A rate of 48kHz means there are 48,000 numbers per second stored to represent the...
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    Voltage regulator circuit

    I agree with FlyingPenguin. It is very unlikely your preamp will care about the 3 extra volts. Putting diodes in series will drop about 0.7 volts per diode, but this should be, as he said, totally unnecessary. Go for it.
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    K7S5a board revision

    You might also want to check the bus speed in the bios. My K7S5a defaults to 100/100 MHz and it doesn't recognize the 1700 xp correctly until I set for 133/133 MHz.
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    thermal expansion

    The huge majority of solids expand when heated. There must be a few exceptions, but there are very few.
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    My CPU is an Athlon XP 1800+, but is now a Duron 1.1Ghz...

    I've had that problem with that board and an XP 1700+. The bus speed resets to 100 MHz rather than 133. The time/date also reset to several years ago. In my case, the problem is probably a soft power supply. I just go into setup and fix the bus speeds and it's OK. No long term problem with...
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    Help installing coax (cable tv) upstairs

    It's possible your cable is acting as an antenna and in fact there is no connection on the other end. But, it sounds as if you got the coax connector on wrong. You said you cut away the shield. You shouldn't do that. The shield needs to be electrically connected to the threaded part of the...
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    About ECS (a fair warning)

    I have to join the others who have found their ECS boards to be satisfactory. This L7S7A2 with an XP2400 has been doing a fine job for a year and a half now. I'm a pretty low impact user, but there have been exactly zero problems. My wife's K7S5A + 1700 is over 2 years old - no troubles. My...
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    Disk cleanup fails

    I have windows disk cleanup hang too. I don't know why I keep trying - it never works. It's a minor annoyance, but if anyone knows how to fix it, I'll give it a try.
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    power factor in 3-phase current

    The sqrt 2 comes in when relating the peak to the rms value for a sine function (either V or I). So there wouldn't need to be a sqrt 3 for three phase systems. And, it wouldn't be sqrt 2 for nonsinusoidal voltages and currents.
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    AC/DC adapter regulated?

    Do you mean the "wall wart" type? I belive most, if not all, are unregulated.