Whats The Wattage In Bkk?

[Crossy]

"Even a resistor has voltage noise which goes as the square root of its resistance "

What gives rise to this noise?

Random movement of electrons.

On high value resistors it can be significant, that's why you see labels saying 'low noise' on what is essentially a passive component.

And it gets worse as the temperature of the resistor increases. More heat, more electron movement which also causes the resistor to change resistance.

An in-depth discussion here:-

http://www.aikenamps.com/ResistorNoise.htm

for anyone really interested.

[chownah]

"Even a resistor has voltage noise which goes as the square root of its resistance "

What gives rise to this noise?

<{POST_SNAPBACK}>

Random movement of electrons.

On high value resistors it can be significant, that's why you see labels saying 'low noise' on what is essentially a passive component.

<{POST_SNAPBACK}>

What causes the random movement of the electrons? Is it cosmic radiation? Is it quantum mechanics effects? Is this noise only a problem in modern computer technology where the number of electrons involved in each change of bit value is relatively small?...or is it a problem at the level of analog audio equipment? I'm interested...I've never heard of this before..maybe a link?

Edited November 10, 2005 by chownah

[Tywais]

"Even a resistor has voltage noise which goes as the square root of its resistance "

What gives rise to this noise?

Random movement of electrons.

On high value resistors it can be significant, that's why you see labels saying 'low noise' on what is essentially a passive component.

What causes the random movement of the electrons? Is it cosmic radiation? Is it quantum mechanics effects? Is this noise only a problem in modern computer technology where the number of electrons involved in each change of bit value is relatively small?...or is it a problem at the level of analog audio equipment? I'm interested...I've never heard of this before..maybe a link?

http://www.dataforth.com/catalog/doc_1065.html

http://www.ecircuitcenter.com/Circuits/Noi...s/res_noise.htm

http://www.csus.edu/indiv/n/ngw/EEE-243/Noise.ppt

http://www.eee.bham.ac.uk/collinst/ee3b1/slides/Noise2.ppt

[Jim 50]

Is the wattage in BKK is it 220 or 110?

<{POST_SNAPBACK}>

I have used both 110 and 220.

The 220 seems to have longer life.

[stumonster]

the square root bit is interesting as flow velocity is the square root of the differential pressure accross an oriface.

[Crossy]

"Even a resistor has voltage noise which goes as the square root of its resistance "

What gives rise to this noise?

Random movement of electrons.

On high value resistors it can be significant, that's why you see labels saying 'low noise' on what is essentially a passive component.

What causes the random movement of the electrons? Is it cosmic radiation? Is it quantum mechanics effects? Is this noise only a problem in modern computer technology where the number of electrons involved in each change of bit value is relatively small?...or is it a problem at the level of analog audio equipment? I'm interested...I've never heard of this before..maybe a link?

Hey Jim, stop trying to get this thread back on topic, we're enjoying ourselves

Back off topic:-

Tywais posted some excellent links.

Resistor noise is only a problem in analogue equipment (its levels are too small to have a significant effect in the digital world). The link in my previous post talks about its effects in valve (tube) guitar amplifiers.

Link repeated for convenience http://www.aikenamps.com/ResistorNoise.htm

Now should an Alpha Particle happen along and absorb one of the electrons from a small architecture DRAM cell it could result in a state change, there's fun for you, and a whole new course for this thread to take.

Ironwolf had no idea what his typo would start

Edited November 10, 2005 by Crossy

[Tywais]

Now should an Alpha Particle happen along and absorb one of the electrons from a small architecture DRAM cell it could result in a state change, there's fun for you, and a whole new course for this thread to take.

Working at a nuclear physics lab one of my primary roles is as chief engineer. I design both analog and digital control/monitoring sytems and have to be really carefull were I place my electronics. Some are in the accelerator area where there are substantial amount of x-rays and gamma rays with a smidgeon of neutrons. I shield them with lead if I absolutely must put them in this enviornment.

Have had bit changes in PROM memory from particle hits and have to reprogram them. Don't put those in this environment anymore. Our biggest problems is that we have CCD cameras spread across the beam line to monitor the electron beam on view screens. After awhile you will start seeing little white dots as the CCD cells die out one by one. Have to replace them after about a year. Have been trying to get X-ray lead glass to put over the lenses to stop this destruction but the companies have not responded to me yet.

Alpha particle can be stopped pretty much with a piece of paper, gamma requires lots of lead.

So here you go, a whole new course for the thread.

[chownah]

"Even a resistor has voltage noise which goes as the square root of its resistance "

What gives rise to this noise?

<{POST_SNAPBACK}>

Random movement of electrons.

On high value resistors it can be significant, that's why you see labels saying 'low noise' on what is essentially a passive component.

<{POST_SNAPBACK}>

What causes the random movement of the electrons? Is it cosmic radiation? Is it quantum mechanics effects? Is this noise only a problem in modern computer technology where the number of electrons involved in each change of bit value is relatively small?...or is it a problem at the level of analog audio equipment? I'm interested...I've never heard of this before..maybe a link?

<{POST_SNAPBACK}>

Hey Jim, stop trying to get this thread back on topic, we're enjoying ourselves

Back off topic:-

Tywais posted some excellent links.

Resistor noise is only a problem in analogue equipment (its levels are too small to have a significant effect in the digital world). The link in my previous post talks about its effects in valve (tube) guitar amplifiers.

Link repeated for convenience http://www.aikenamps.com/ResistorNoise.htm

Now should an Alpha Particle happen along and absorb one of the electrons from a small architecture DRAM cell it could result in a state change, there's fun for you, and a whole new course for this thread to take.

Ironwolf had no idea what his typo would start

<{POST_SNAPBACK}>

Interesting stuff. In you link I found this:

"Contact noise

Contact noise is dependent on both average DC current and resistor material/size. The most significant contributor to noise in guitar amplifiers is the use of low-wattage carbon composition resistors. Since the noise is proportional to resistor size, the use of 2W carbon comp resistors will improve the performance over that of 1/2W resistors. Studies have shown a factor of 3 difference between a 1/2W and a 2W carbon comp resistor operating at the same conditions. "

I think they made a mistake. Shouldn't it say that the noise is INVERSELY proportional to resistor size? This would make a smaller resistor noisier and a bigger resistor quieter....I'm assuming that a 1/2 W resistor is smaller than a 2W resistor.

[quadricorrelator]

I was concerned with "thermal noise" in resistors. Thermal noise depends on the value of the resistor (I don't know about "contact" noise). I do not know the about the physics of noise (yet). But, I do know its characteristics.

You can model resistor noise as a voltage source (a battery) in series with the resistor. The voltage of this battery is a random process whose frequency spectrum is constant at all frequencies. But all circuits are have limited bandwidth, so the amount of noise is limited as by this as well. The stray capacitance across the resistor will limit the bandwidth of any signal flowing through it. The wire connected to the resistor will have inductance and that can play a role as well (it can even resonate with the stray capacitance).

The probability density function for the random resistor voltage at any point in time is a Bell curve (normal curve). Its standard deviation is proportional to the square root of the resistance, the temperature, and the bandwidth of the circuit.

You can equivalently model the noise source as a current source in parallel with the resistor. In this case the current goes inversely with the square root of the resistance.

The effect of noise on overall circuit performance depends on how you are using the resistor.

Every resistor and every transistor in the circuit degrades circuit performance to some extent. You have to add up the contributions from each noise source to find the overall effect.

In the design of highly sensistive, high speed photodiode amplifiers for fiber optic communications, I found that I wanted to use large resistors. The voltage noise from the resistor goes as the square root of the resistance, but the voltage signal was directly proportional to the resistance since this voltage was generated by a current going through the resistor (ohm's law determined the voltage).

The noise increased as the square root of the resistance, but the signal was amplified in proportion to the resistance, so it was best to use the biggest resistor possible.

In this case, I the amplifier was analog, although I was amplifying a digital signal. Bit errors were made according to the amount of noise in the circuit.

[Sir Burr]

Was wondering how a thread entitled "Wattage in Bangkok" could get to seven pages, so, thought I'd have a looksee.

Must be in a time warp. I feel I'm back in Mr. Clarke's physics class..........minus the size 13 slipper for inveterate fidgeters and chatterers.

[chownah]

.............

The probability density function for the random resistor voltage at any point in time is a Bell curve (normal curve).  Its standard deviation is proportional to the square root of the resistance, the temperature, and the bandwidth of the circuit.

............

<{POST_SNAPBACK}>

Is the mean of this curve at 0 volts of random voltage? seems like it would have to be....or else the resister itself would be acting as a net voltage source...which of course it could not be......is my thinking correct here?

Seems like you are saying that in addition to the audio processing being subject to resistor noise that digital processing is effected too...at least in the application you are describing. At least in communications applications errors can be found and the data retransmitted to solve the problem. In a cpu you want to avoid these kinds of errors altogether...do you know if these resistor noise issues are active in cpu or memory chip design or interfaces?

[jonik]

just a tought ..........attach one cord of your 110v hairdryer to the shower(make sure its of metal) in you bathroom and the other one into the outlet.You ll might be able to use it. SURE SURE

[jonik]

And if someone is screaming it does not consern you ,just keep up the good work.

[RDN]

....Now should an Alpha Particle happen along and absorb one of the electrons from a small architecture DRAM cell it could result in a state change,...

<{POST_SNAPBACK}>

That's the excuse that DEC (Digital Equipment Corp) came up with when one of our computers stopped dead for no apparent reason - "Must've been a stray cosmic particle"

[quadricorrelator]

.............

The probability density function for the random resistor voltage at any point in time is a Bell curve (normal curve).  Its standard deviation is proportional to the square root of the resistance, the temperature, and the bandwidth of the circuit.

............

<{POST_SNAPBACK}>

Is the mean of this curve at 0 volts of random voltage? seems like it would have to be....or else the resister itself would be acting as a net voltage source...which of course it could not be......is my thinking correct here?

Seems like you are saying that in addition to the audio processing being subject to resistor noise that digital processing is effected too...at least in the application you are describing. At least in communications applications errors can be found and the data retransmitted to solve the problem. In a cpu you want to avoid these kinds of errors altogether...do you know if these resistor noise issues are active in cpu or memory chip design or interfaces?

<{POST_SNAPBACK}>

"Is the mean at 0 volts?"

Yes, you are correct, and your reasoning is also correct. In fact, if you know the resistance of the resistor, you can determine the actual variance of the voltage. I mean you can take many samples of the voltage across the resistor and you will get a Bell curve centered at 0 volts. I will tell you how to predict the various just from knowing the resistance after answering your second question.

"Is digital processing effected too?"

Yes, it is. Suppose you are receiving a digital signal that has been transmitted from far away (a radio signal, fiber optic signal, etc.). Your signal may be very small and you must amplify it before it can be used. Your amplifier could add more noise than the signal if it is not properly designed. The ratio of the signal power to the noise power will determine the number of errors you get per second. This is a measure of the sensistivity of the amplifier. It is often a critical specification and technical wars are fought by engineers (between companies) over this specification.

Similar issues apply to reading of disk drive data.

Inside the CPU, I believe that most of the circuitry does not use resistors. CPUs use transistors call CMOS (complementary metal oxide semiconductor). I do not have much knowledge about the error rates inside the CPU since I don't have experience in that area. I suspect they do use error correction techniques in various places. I think that the memory chips also probably use error correction techniques.

****************************************

Demystifying resistor noise calculations (at least I am trying to do that):

Noise in a resistor: I want to make a simple calculation (about the difficulty of ohm's law) to show that resistor noise is concrete, tangible, and measurable. It is not some mysterious entity that you have to guess about.

First let me tell you a magic number! It's the only number you'll ever need for resistor noise. It is this: A 1000 ohm resistor has 4 nanovolts per square root hertz (bandwidth). This is the value of the voltage source in series with the resistor.

Why is it the only number you'll ever need? Suppose you had a 4000 ohm resistor and you wanted to know the noise. Since it is 4 times the resistance, it has twice the noise. It would have 8 nanovolts/root hertz. Suppose you had a 9000 ohm resistor, it would have 12 nanovolts/root hertz. The noise goes as the square root of the ratios of the resistances (a 50 ohm resistor would give about 1 nanovolt/root hertz).

Noise of Resistance R = square root (R/1000) * 4 nanovolts/ square root hertz

How do we use this number? What do you do with the 4 nanovolts/per root hertz?

Here's how to use it: Let's say you take the 1000 ohm resistor and connect it to a filter which passes all signals below 1 megahertz. Let us also assume that the amplifier does not interact with the resistor at all. That is, the amplifier doesn't draw any current from from the resistor (it is an ideal amplifier).

So, all noise from the resistor that is below 1 megahertz will pass through the filter. Let us take random samples of the voltage every second, from the output of the filter. You will get a Bell curve whose average is 0 volts (as you said), and whose variance is 4 microvolts. That means that 68.3% of the random samples will be within +/- 4 microvolts (of 0).

How do I arrive at +/- 4 microvolts? You get this number by taking the square root of the bandwidth (1,000,000 hertz) and multiplying that by 4 nanovolts/ square root hertz. So, the variance = 4 nanovolts/root hertz * square root(1,000,000 hertz)

= 4 nanovolts/ root hertz * 1000 root hertz = 4 microvolts!

One qualification is that this calculation is made at room temperature (300 kelvin or 27 degrees Centigrade). You must scale the voltage noise as the square root of the absolute temperature.

One last item: If you are trying to calculate the total noise at the output of your amplifier, you must find the contribution from each noise source first. Then you add the sources in as a sum of square roots of the squares of the voltages. If you have three resistor contributing v1, v2, and v3, then then total noise will be

square root (v1*v1 + v2*v2 + v3*v3

Edited November 10, 2005 by quadricorrelator

[jonik]

And if you take the nanovolts and skip the resistance of the inducted ferrositt ,the inductance is higher than the rebound of the coil passing trough it.The PCU will then upgrade for big hertz ohm inside the capacitator,whiles the exelent silisium transits conduct flowing force.

It is absolutely exelent.

[dr_Pat_Pong]

Bugger me

[quadricorrelator]

"Thank you, I find it interesting, and do care.

I was looking at the previous post really, about the maths genii (?) who tried to beat the market. Of course, like everybody else, they were successful when the market was bouyant. The admission that their maths was incorrect is no surprise, the market movements are so random as to be incoherent.

Maybe their incoherency formulae (better) would work. "

Oddly enough, these genuises managed to fail when the market was still going up, in 1998. The hedge fund went up 300% in the first four years, and then dropped over 90% in about two months.

According to what I read, the fund failed because their methods relied very heavily on fine details of historical market data, but the market followed those trends for only a few years before doing something unexpected.

According to Eugene Fama (a famous economist), modeling the market as Brownian motion (a particular kind of random process used by economists in market modeling) is accurate for about three or four years (on the average) before breaking down.

Edited November 11, 2005 by quadricorrelator

[chownah]

"Thank you, I find it interesting, and do care.

I was looking at the previous post really, about the maths genii (?) who tried to beat the market. Of course, like everybody else, they were successful when the market was bouyant. The admission that their maths was incorrect is no surprise, the market movements are so random as to be incoherent.

Maybe their incoherency formulae (better) would work. "

Oddly enough, these genuises managed to fail when the market was still going up, in 1998.  The hedge fund went up 300% in the first four years, and then dropped over 90% in about two months. 

According to what I read, the fund failed because their methods relied very heavily on fine details of historical market data, but the market followed those trends for only a few years before doing something unexpected.

According to Eugene Fama (a famous economist), modeling the market as Brownian motion (a particular kind of random process used by economists in market modeling) is accurate for about three or four years (on the average) before breaking down.

<{POST_SNAPBACK}>

What was the event or situation that caused the market to do something unexpected so that the hedge fund dropped 90% in about 2 months?

[Boon Mee]

"Thank you, I find it interesting, and do care.

I was looking at the previous post really, about the maths genii (?) who tried to beat the market. Of course, like everybody else, they were successful when the market was bouyant. The admission that their maths was incorrect is no surprise, the market movements are so random as to be incoherent.

Maybe their incoherency formulae (better) would work. "

Oddly enough, these genuises managed to fail when the market was still going up, in 1998.  The hedge fund went up 300% in the first four years, and then dropped over 90% in about two months. 

According to what I read, the fund failed because their methods relied very heavily on fine details of historical market data, but the market followed those trends for only a few years before doing something unexpected.

According to Eugene Fama (a famous economist), modeling the market as Brownian motion (a particular kind of random process used by economists in market modeling) is accurate for about three or four years (on the average) before breaking down.

What was the event or situation that caused the market to do something unexpected so that the hedge fund dropped 90% in about 2 months?

In the vernacular it's called 'Pump & Dump'

[chownah]

"Thank you, I find it interesting, and do care.

I was looking at the previous post really, about the maths genii (?) who tried to beat the market. Of course, like everybody else, they were successful when the market was bouyant. The admission that their maths was incorrect is no surprise, the market movements are so random as to be incoherent.

Maybe their incoherency formulae (better) would work. "

Oddly enough, these genuises managed to fail when the market was still going up, in 1998.  The hedge fund went up 300% in the first four years, and then dropped over 90% in about two months. 

According to what I read, the fund failed because their methods relied very heavily on fine details of historical market data, but the market followed those trends for only a few years before doing something unexpected.

According to Eugene Fama (a famous economist), modeling the market as Brownian motion (a particular kind of random process used by economists in market modeling) is accurate for about three or four years (on the average) before breaking down.

<{POST_SNAPBACK}>

What was the event or situation that caused the market to do something unexpected so that the hedge fund dropped 90% in about 2 months?

<{POST_SNAPBACK}>

In the vernacular it's called 'Pump & Dump'

<{POST_SNAPBACK}>

What I'd like to know is what happened in the real world to make the fund values drop....did people stop buying real estate....did they stop growing hedges...did someone develop some new product or process...did something happen in the real world that effected the funds so they lost value?

[paulfr]

"Thank you, I find it interesting, and do care.

Oddly enough, these genuises managed to fail when the market was still going up, in 1998.  The hedge fund went up 300% in the first four years, and then dropped over 90% in about two months. 

According to what I read, the fund failed because their methods relied very heavily on fine details of historical market data, but the market followed those trends for only a few years before doing something unexpected.

According to Eugene Fama (a famous economist), modeling the market as Brownian motion (a particular kind of random process used by economists in market modeling) is accurate for about three or four years (on the average) before breaking down.

<{POST_SNAPBACK}>

What was the event or situation that caused the market to do something unexpected so that the hedge fund dropped 90% in about 2 months?

<{POST_SNAPBACK}>

In the vernacular it's called 'Pump & Dump'

<{POST_SNAPBACK}>

What I'd like to know is what happened in the real world to make the fund values drop....did people stop buying real estate....did they stop growing hedges...did someone develop some new product or process...did something happen in the real world that effected the funds so they lost value?

I saw a one hour special TV program on this group of men and their fund.

It was on Frontline in the US.

As I recall, what happened was an Asian Real Estate market crash that spread

thru the capital system back to the West. It was a disaster and very frightening that

one fund could cause so much of a threat to the world financial system. This of course

is why they were bailed out by some major banks and funds. That could not be allowed

if at all possible.

Moral: Even the brightest minds are not invincible. And as some would say ..

"Those whom the gods would destroy, first they fill with arrogance"

[rellevart]

Hi, I need help here. I am from Singapore. My recent visit to BKK, when I want to recharge my chargeable batteries, I put in an international pin, add a foreign electricity converter and plug my charger. Immediately my charger got shock and was burnt. Ended up, no rechargeable batteries for my camera and now I need to buy a new charger. I may visit Thailand again. Please let me know where gone wrong. Tks.

[MarkBKK]

Hi, I need help here. I am from Singapore ... Please let me know where gone wrong. Tks.

Buying AIS.

[Chang_paarp]

Hi, I need help here. I am from Singapore. My recent visit to BKK, when I want to recharge my chargeable batteries, I put in an international pin, add a foreign electricity converter and plug my charger. Immediately my charger got shock and was burnt. Ended up, no rechargeable batteries for my camera and now I need to buy a new charger. I may visit Thailand again. Please let me know where gone wrong. Tks.

With an adaptor you should be fine to use the wall socket. Sing and Thai use 240V 50 hz.

Did you stay in a better class of hotel that has a socket in the bathroom for razors? Some of those are for the US 110V razors, using that one could be interesting . It would have been spectacular to watch.

[Pink Mist]

OHM'S LAW

Resistance, R = Voltage/ Current = [ohm]

Current, I = Voltage/Resistance = [ampere]

Voltage, V = Current x Resistance =volt]

I = E/R

where I = Power, E = Voltage, R = resistance where Voltage & resistance are the known factors.

can you state Ohms law in words rather than formula?

[The Skipper]

230v

That's what my meter says when I check my house voltage.

[tom yum goong]

my brain hurts after reading all that.

[backflip]

Dang, you forgot the most important one: power = voltage X amperes.

[Chang_paarp]

Dang, you forgot the most important one: power = voltage X amperes.

Power (in Watts) = Volts x Amps