# What is the nature of the two bits of data held in a computer memory cell?

I hope this question doesn't offend anyone. I start off by saying that I have and always had difficulty understand the language used in computer science so I have to interpret everything into the language of physics of electronics.

First what is termed as memory, I seem to think that it refers to energy that is held basically in one of two forms, either in an electric field or a magnetic field. And what is referred to a memory cell is the mechanism ( a physical thing) that this field is held. I have noticed that for all practical purposes memory/energy is held in an electric field.

It appears to me what is called a memory cell is made of two physical mechanism, a capacitor that the electric field is contained and a transistor to access the memory, i.e. the energy held in that electric field of the capacitor.

What is termed as word-line seem to refer to the conductor that goes to the gate of the transistor, and what is termed as bit line is a connection to the Drain part of the transistor. And the capacitor that the energy is held is connected to the Source part of the transistor.

Furthermore, it appears that the word-line is a way to access the energy while the bit line does two things, in-put and out-put. I seem to interpret the input as charging the capacitor and the output is when the charge is released back, accessed, coming back from the capacitor.

If I had all that correct only then my question perhaps have meaning otherwise it can not be answered. I had to describe all the above just to save a whole lot of back and forth and the effort for someone else to explain the details in language I won't understand. This of course I assume that what I have described in itself understandable in the first place even if it is false, that is.

Since in computer language information/memory/data is represented in binary, i.e. 0 and 1.

My question is: Does 1 ( in computer language) means that the capacitor is charged? Does the 0 mean that the capacitor is discharged, meaning it is dead, like a dead battery?

Or Does 1 mean that the capacitor is charged with some higher voltage value? And the 0 mean that the capacitor is charged in some lower voltage value?

I can understand the 1 to mean some voltage value. But I can not understand the capacitor being dead, fully discharged as to mean 0.

Why do I have difficulty with the 0 interepetation of a dead no voltage capacitor? Because in the particular memory cell, the presence of a capacitor would be meaningless. And I should say that I specifically am referring this to what is termed as paramenent memory that is established in the factory, not-erasabale or rewritable.

Furthermore an obsence of voltage, or 0 is already the case by default. In other words if there is nothing to read, it then has to be interepreted as reading "nothing to read". Or when programming a 0, it would mean you don't do anything to the particular cell as it is in a discharged state by default.

And one more question which is the right thing to do. When a permanent memory is accessed ( i.e. read) the capacitor is discharged, the bit line having a larger value voltage due the discharge of the capacitor. Now this discharge state of the capacitor can not remain as it does not have infinite charge. It has to be recharged immediately and this can only be done by the same bit line ( as write). Is this correct? Furthermore this must be the value 1, bit 1. And if the particular cell is value of 0, there is nothing to read or write and by default that cell is interpreted as 0 as no voltage is there in the bit line as reading and no current will be sent as input/writing.

I am sorry, that I have typed so much and have not kept my question direct and simple. I have only done with genuine intention to save the headache tring to explain and make their answer easier for them.

So brief and to the point now: Does 1 represent presence of voltage or some higher voltage? Does 0 represent no voltage or some lower voltage but voltage nontheless? Does ROM ( factory non-writeable, no-erasable, non-changeabale) cell needs to be charged to retain its factory setting? In a floating gate transistor cell ( looking at the diagram) in what part of that gate, electric field is held, (if the floating gate itself is made of two membrane or...)? Thank you.

• This question sounds like a question about electrical engineering rather than computer science. Generally, CS concerns itself with anything at the level of bits or above; anything at a lower level of abstraction, such as how bits are implemented with transistors and circuits is generally a matter of EE. Any community votes whether this is on-topic or off-topic?
– D.W.
Jul 19, 2021 at 5:23
• To me, it sounds to me more like electrical engineering. However, this is still an interesting question! Jul 19, 2021 at 7:55
• Nir shahar, take a look at the capacitor in the diagram. And the transistor. What is called memory/data/information? It is the energy stored in the electric field of the capacitor and what is called the cell that stores the memory/energy is the capacitor. What is termed as word line is the conductor to the gate and what is called bit line ( and so called in put and out put) refers to the source side of the Mosfet connection. The drain side is where the capacitor sits. In the floating gate this capacitor in sandwitched in the gate. You can clearly see it.
– Ali
Jul 21, 2021 at 20:10
• Nir shahar, I also know the exact detail of operation, the actual principle of operation and values. The only thing I don't know is I don't know the real mechanics of what the stuff is that they are made of. Which I don't blame them corporations. Besides a human being can't make them anyway. They are too small. Get this, the capacity of those capacitors are in femtofarad and the floating gate is even far less than that. That happens with tunneling. Of course the diagram is not going to reveal this. Cheers.
– Ali
Jul 21, 2021 at 20:16
• Nir shahar, if you actually care to know how the whole thing works and what it is all about just let me know. I have no desire to ramble on just to read my own typing.
– Ali
Jul 21, 2021 at 20:23

At a very low level, a hardware designer will decide what means 1 and what means 0. For example, they might say "Anything above 3.7V means 1, and anything below 1.9V means 0, and any voltage in between should be avoided and shouldn't happen.

And then they design a NAND gate with three inputs and say "If all three inputs are above 3.7V then the output will be 0.5V, but if any input is below 1.9V then the output will be 4.5V. If any inputs are between 1.9V and 3.7V then no guarantee what the output is".

And above that level, we can completely forget about the hardware level.

• Indeed. A computer science expert perhaps could benefit what is behind them 0s and 1s lingo's and if the values, any of the two values are truly distinct or a range of values. I agree. Thank you. You are the first that didn't shy away from answering because you were aware of my basic direct inquiry. And you didn't treat me with being in the wrong department, nor dismiss my question in various ways, etc. And I can be assured that if anyone voting me out, I am more than certain it wouldn't be you. And I appreciate that.
– Ali
Jul 20, 2021 at 3:39
• To be fair and true to myself , sifting through all the abstractions I do know the answer now after I posted and to every part of my question. And in a simple direct clear reader's digest language. It took a lot of digging I must admit and yes with a bit of luck. Now I can be voted out if need be.
– Ali
Jul 20, 2021 at 3:52
• Thank you very much. Meaningful clear answer. Worthy of thumbs up.
– Ali
Aug 19, 2021 at 5:29