What are the Charges in the the cathode and the anode???????

Question

Earlier today in my science class we were discussing cathodes and anodes, The book I was reading (Glencoe Science) said that the anode had a positive charge where as the dictionary and my teacher said the opposite. I figure an= anti = negetive I really don't know!!!!

Answer 1

A cathode is negatively charged electrode, as of an electrolytic cell, a storage battery, or an electron tube.

An anode is a positively charged electrode.

You are right.......Some students are smarter than their professors....Plus they can get old and senile(lol)

Answer 2

Electrons have what is defined as a negative charge, and are attracted to a positive charge, which is actually a "hole", an atom that has an electron missing in its outer shell. A vacuum diode tube has a filament, which is heated by current such that electrons boil off of it and are then attracted to the positively charged anode. Since the anode doesn't have a filament with boiling electrons available, an AC signal across the tube will be rectified into pulsating DC, and all electron flow will be from the cathode, which since it has all the exceess electrons is negatively charged, to the anode, which with its positive charge is able to attract the electrons.

Double-check the dictionary and what your teacher said, because as you state it, they are most definitely incorrect.

Do not confuse current flow, which can go either way depending on whether you are talking about "electron flow" or "hole flow", with the concept of charge, which is defined and fixed in definition of electrons being negative, and there is no convention that would allow one to refer to an anode as having a negative charge. Feel free to email me if this isn't clear.

Now, you can put a reverse bias across a diode, in other words, apply a negative voltage to the anode with respect to the cathode. But no current will flow - the switch will be "off". But that has nothing to do with what you're asking. And here it is from wikipedia -

"Flow of electrons
The flow of electrons is always from anode–to–cathode outside of the cell or device, and from cathode–to–anode inside the cell or device, regardless of the cell or device type. Inside a chemical cell, ions are carrying the electrons but the flow is still from cathode–to–anode inside the cell."

Of course, we're talking about "inside the device", the current thru it.

Feel free to email me if this isn't clear.

Answer 3

I always got confused with that myself. I remember learning that the a(n)ode was negative and the ca(+)hode was positive. I think the confusion came when we were talking about batteries. We usually talk about the flow of positive charges when talking about electrical current (even though it is really the electrons (-) that are doing the moving.) Anyhow, lets look at the positive charges.

On the inside, positive charges are moving from the anode to the cathode.

Looking at the battery from the outside, positive charges move from the cathode to the anode.

(Look at the comments on vacuum tubes - the anode is considered positive for them - it seems to defy convention)

Answer 4

Dont get confused, All the books or majority of them good ones says Anode is positive. Cathode is Negative.

A simple proof is the Cathode Ray Tube (CRT) or simply put the picture tube of our good ol TV set . Its so called because electrons are inside it, continously being fired(ray) to the face of the tube to light up the screen . electrons are negatively charged, and they are inside the tube . thus they call it "cathode ray tube".

Answer 5

Cathode is negative charged ( because cations(+) come to Cathode)
Anode is possitive charged ( because anions(-) come to anode)

Answer 6

Cathode = +
Anode = -