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Comment by Gibbon1 | Hacker News Reader

Anytime electrochemistry is involved it's important. But regular electronics not very much. I think positive and negative mostly trips up people trying to use what they think is happening to explain theory. When it's not that useful most of the time.

What I could never keep straight is anode and cathode.

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It's easy! Cations are positively charged, so cathodes are, uh, negatively, charged. With anions and anodes it's the other way around.

It makes perfect sense! Cations, you see, are attracted to anions. And reduced by cathodes. Anions? Attracted to cations. And oxidized by anodes.

Whereas cations are oxidized by anions, and anions are reduced by cations.

The only alternative here would be if cathodes and cations were positively charged, and anodes and anions were negatively charged. But then cathodes would reduce anions, and cations would also reduce anions. Even worse, anodes would oxidize cations, and anions would also oxidize cations.

And we can't have that. It would just be too confusing.

The other day, I was reading a chemistry book at the point where it "helpfully" listed four different mnemonics for the same thing -- cations vs. anions, or maybe it was cathodes vs. anodes, or anyway, you know, something in that vicinity.

I just let my eyes skip over that list. I refuse to be the Jaguar in "Just-So Stories" https://etc.usf.edu/lit2go/79/just-so-stories/1294/the-begin...

It doesn't help that very many explanations on the web of anode/cathode are wrong, or at least misleading, and only cover catalytic or galvanic cells.

I believe https://chemistry.stackexchange.com/questions/16785/positive... is correct.

The terms "anode* and cathode have their own problems. The cathode is that terminal of a device where positive current emanates. The (+) terminal of a batter is normally a cathode, but when the battery is being charged, it becomes an anode.

The terms anode and cathode should be burned. We don't use them much in modern electronics. E.g. we don't say that the positive power pins of a CPU are anodes, or that ground pins are cathodes.

A CRT display is a "cathode ray tube", which shoots electrons, which are negative.

CAThodes are PAWsitve

But if you connect a 5V battery in parallel with a 4V battery, the 5 will try to charge the 4. So the (+) terminal of the 5V battery will act as a cathode, but the (+) terminal of the 4V battery as anode.

"CCD" -> "cathode: current departs"

In chemistry though, cations are positive ions and anions are negative ions.

My personal mnemonic for that is that the letter A is often used for getting the opposite meaning of words (moral/amoral, sexual/asexual), and even moreso in my native (non-english) language. Thus my brain wired itself to associate "anode" with negative. It's quite a stretch but my mind seems to form a bunch of these weird mnemonics.

Cats are more intelligent than donkeys (âne in French). Cathode is positive, anode is negative. That's how I (and probably all French students) learned it.

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