Does an USB stick gain weight when you put files on it?

Does an USB stick gain weight when you put files on it? or to put it a different way: Are electrons from outside used to store data on an USB stick?

Since I'm quite new to electronics I cannot give a logical explanation. I searched a lot on the web and I found the folowing data:

? Flash memory uses the Fowler?Nordheim tunneling principle to charge a thin oxide layer ? Excited electrons are pushed through and trapped on other side of a thin oxide layer, giving it a negative charge ? The negative charge give the floating-gate transistor a value of '1' or '0'

Although I can imagine how the principle works, I do not fully understand the exact technics.

USB sticks need power supply to read and alter the data on it. But when information is added, has the amount of electrons increased?

Consider the stick is fully empty at the beginning (all transistors are not negatively charged and thus have the status of '1')

Bert

Reply to
Bert Harleman
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Is a charged capacitor heavier than an uncharged one?

Tom

Reply to
Tom Biasi

The USB device will remain overall neutral in charge, else it would soon attract or repel the appropriate charge from/to its environment and neutralize. So don't look for added or removed electrons for a change in weight.

Instead, consider that there is some energy storage in the form of binding energy for the trapped electrons in the gates. This energy will have some equivalent mass via E = m*c^2. It'll be all but unmeasurable.

Reply to
Greg Neill

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Hmm, I'm going to say it's heavier when it's charged. I've had to do some work to move the chagres around and that energy is stored in the electric field. Lets say a 1 Farad cap charged to 1 kV. an enregy of

1 Mega Joule (I ignored the 1/2 term.) Call c^2 =3D 10^17 and that's 10^-11 kg or 10^-8 grams.... going be pretty hard to measure on my micro balance.

George H.

Reply to
George Herold

I reckon if there is a difference in weight it will be utterly small But it's more about the principle of the system in Flash memory

Reply to
Bert Harleman

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In a word, "yes".

JF
Reply to
John Fields

.... going be pretty hard to measure on my micro balance.

George H.

Charged one in one hand, uncharged one in the other hand, close your eyes and move them up and down a little. You should be able to tell.

Tom

Reply to
Tom Biasi

No, the amount of electrons is not, on the whole, going to increase. You're injecting electrons into the gates of the MOSFETs, but you're taking them out of the nearby semiconductor.

The gate of a 'written' flash cell does have some stored energy, so the memory stick will -- in theory -- get heavier, to the tune of E = mc^2. But you'll probably scrape more mass onto or off of the thing plugging it into and out of your computer than you add by writing all those cells.

--
www.wescottdesign.com
Reply to
Tim Wescott

Firstly, any REAL memory stick will be fully programmed, either zero or one, in all cells, before you get it. There isn't any way to know if 'zero' is low-field-energy or if 'one' is low-field-energy, unless you have insight into the internal architecture of the stick.

Space unused for files is often filled with a pattern to aid in quick checks of system integrity, hexadecimal 'feedface' and the like are highly likely patterns for a no-data-here flash drive's empty blocks.

The total count of 'zero' or 'one' bits does have some associated energy, thus a very small amount of mass can be changed. But this is not associated with 'information' directly, any non-information- content random pattern with the same number of bits in the ON and OFF state will be the same energy content.

Reply to
whit3rd

No. Data is stored as charges on capacitance. No net collection of electrons results in the charging or discharging of a capacitor. A capacitor is a two terminal device. When you charge it a current flows into one terminal and an exactly equal current flows out of the second terminal. This is what Maxwell called displacement current and is the basis for our understanding of current flow in a series circuit. The current there is everywhere the same and if it is the same, there can be NO net collection of electrons anywhere in the circuit. What we have in a charged capacitor is an influence of the electrons across a voltage gradient and not a collection or "bucket" of electrons. Therefore there can be no increase or decrease in mass because the total number of electrons is constant. Furthermore there is no mass to energy conversions or other nuclear processes occuring.

Reply to
Bob Eld

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