Admit your Brain lock

[TimNJ]

After about 15 years, I've finally remembered which side of the diode symbol is "cathode" and which is "anode". 

It will be another 15 years to remember whether the long lead of an LED is the cathode or anode.

[IanB]

After about 15 years, I've finally remembered which side of the diode symbol is "cathode" and which is "anode". 

It's honestly best not to use the words anode and cathode, since depending on context an anode can be either positive or negative, and a cathode can be either negative or positive. Those two words should be stricken from the dictionary as being meaningless without context.

Anyone who wants to communicate accurately should say "positive electrode" and "negative electrode" instead.

[coppercone2]

oh yeah those terms suck

[SiliconWizard]

This puts my brain into deadlock (and also tends to trigger some anger, which is a paradox): https://www.europarl.europa.eu/doceo/document/E-9-2023-002312_EN.html

[TimNJ]

This puts my brain into deadlock (and also tends to trigger some anger, which is a paradox): https://www.europarl.europa.eu/doceo/document/E-9-2023-002312_EN.html

Was in Ireland last summer. An absolute immense number of cows. Wow! On the other hand, I saw no evidence of mass factory farming and the ecological disaster that follows (see: Texas). It seems like, if you are going to have a ton of cows, Ireland does it the best way possible. Cows free grazing, tons of room per animal. They looked happy. .So, yes let's kill 200,000 cows and then what happens? Increase the supply in some factory farm hellhole in the UK to meet the supply again?

[nctnico]

This puts my brain into deadlock (and also tends to trigger some anger, which is a paradox): https://www.europarl.europa.eu/doceo/document/E-9-2023-002312_EN.html

Offtopic: It is a very sensible question and drastic action is needed. If you take into account how small the Netherlands is versus the immense agricultural output (second largest exporter of agricultural products after the US), you can only come to the conclusion that a huge reduction of farming activities is required. In some places the soil is more acidious compared to Coca-Cola due to nitrogen deposits which kills nearly all plant life. Yes, we have the very super best of the best farmers of the world in the NL. Please make them stop doing such a good job!

[Sredni]

After about 15 years, I've finally remembered which side of the diode symbol is "cathode" and which is "anode". 

It's honestly best not to use the words anode and cathode, since depending on context an anode can be either positive or negative, and a cathode can be either negative or positive. Those two words should be stricken from the dictionary as being meaningless without context.

Anyone who wants to communicate accurately should say "positive electrode" and "negative electrode" instead.

Nah, just remember that (conventional) current always* goes into the anode and you're good.

Try it connecting a chemical cell to an electrolytic bath: the current exits from the positive pole of the battery (hence not an anode) and enters the positive pole of the electrolytic bath (now it's an anode). Exits the bath from its cathode and enters the battery from its anode.

The swapping of the names happens because of the different convention adopted for sources and sinks: current exits the positive terminal of a battery and enters the positive terminal of a resistor.


*Zener diodes are an exception because we use them backwards.

[SiliconWizard]

When it comes to diodes, they can be used in a number of ways that would make naming the pins + and - very confusing. Anode and Cathode are much more preferable to avoid any possible confusion: it's just a convention that has become unambiguous.

You might argue that it was initially a bad choice, but I'm not sure + and - would have been much better, and obviously changing now a well-established convention would be way worse.

[Circlotron]

Nah, just remember that (conventional) current always* goes into the anode and you're good.

For the sake of upping the ante on the confusion index, with a vacuum tube, when looking from the inside we could say electrons enter the anode, but when looking from the outside the electrons exit the anode connection.

[Sredni]

Nah, just remember that (conventional) current always* goes into the anode and you're good.

For the sake of upping the ante on the confusion index, with a vacuum tube, when looking from the inside we could say electrons enter the anode, but when looking from the outside the electrons exit the anode connection.

Well, I guess that happens with batteries and resistors, as well.
But if you look at components from a circuital perspective, the rule 'current into anode' always hold (apart from those pesky zener diodes, that is).

_{In general, looking inside components can shake one's beliefs about reality: look inside an inductor and you will discover KVL is no longer working; look inside a capacitor and it's KCL that stops functioning.}

[IanB]

Nah, just remember that (conventional) current always* goes into the anode and you're good.

Try it connecting a chemical cell to an electrolytic bath: the current exits from the positive pole of the battery (hence not an anode) and enters the positive pole of the electrolytic bath (now it's an anode). Exits the bath from its cathode and enters the battery from its anode.

This is a useful and helpful aid to understanding, but it does mean that the positive terminal of a secondary cell is its cathode when it is discharging, and is its anode when it is charging. (And logically, has no name when the cell is open circuit, neither charging nor discharging.)

The swapping of the names happens because of the different convention adopted for sources and sinks: current exits the positive terminal of a battery and enters the positive terminal of a resistor.

This description therefore defines anode and cathode operationally according to the sourcing or sinking behavior of the device and not according to the physical nature of the device itself.

*Zener diodes are an exception because we use them backwards.

According to the above arguments, Zener diodes should not be an exception. Like secondary cells, the assignation of anode and cathode should depend on the direction of operating current flow. And should change depending on whether the Zener is being operated in rectifying mode or breakdown mode.

[Sredni]

This is a useful and helpful aid to understanding, but it does mean that the positive terminal of a secondary cell is its cathode when it is discharging, and is its anode when it is charging. (And logically, has no name when the cell is open circuit, neither charging nor discharging.)

The same applies to capacitors and inductors: when you are charging them, positive conventional current enters the positive terminal; when you discharge them on the attached circuit (a resistor, for example), positive conventional current exits the positive terminal.

Regarding the physical (or chemical) nature of the process, rememeber that "OXANa has a RED CAT". I.e. OXidation happens at the ANode, and REDuction at the CAThode.

[Halcyon]

After about 15 years, I've finally remembered which side of the diode symbol is "cathode" and which is "anode". 

It's honestly best not to use the words anode and cathode, since depending on context an anode can be either positive or negative, and a cathode can be either negative or positive. Those two words should be stricken from the dictionary as being meaningless without context.

Anyone who wants to communicate accurately should say "positive electrode" and "negative electrode" instead.

Thanks for un-doing what high school electronics taught me. 

[pcprogrammer]

If I want to remember a number I generally say it out loud and listen to myself saying it.  Then I have a chance, at least for a short while. 

That's a general advice here.

When you're leaving say things out loud.
Stove is off, coffee maker is off, etc.

For this you need Google control. 

Ok, here's mine:  I can't remember numbers, names, or faces without a lot of effort.  I often can't recall the names of people whom I have known for years, it takes a lot of exposure to make a name stick.

Faces, images or written texts stick rather easily, but names need lots of repetitions before they stick. Sometimes indeed a bit embarrassing when you meet someone and have to guess their name.

[SiliconWizard]

It seems everyone's memory has its own ways. As for me, I used to have a hard time remembering complicated paths that I had been exposed to only once or twice when driving, and it took really a number of times for paths to stick. That was before the GPS of course, but even before using this, I got better over time. So, I guess for me that was visual cues that were not as effective as they should be, but that's always something you can work on.

[c64]

Quantum computing.

[Zero999]

The answer is the h_FE is irrelevant to most BJT linear amplifier designs. I_C vs V_BE is what's important.

Nope. If you look at amplifier designs closely, you'll always see voltage to current conversion stages using resistors and other parts (like red LEDs) to cancel the temperature and process dependent Vbe changes / differences.

What I mean by changes in I_C  vs V_BE isn't process dependent variation, but ∆V_BE vs ∆I_C. Take the common emitter amplifier for example. Note the A_V has nothing to do with h_FE.

[tggzzz]

_{In general, looking inside components can shake one's beliefs about reality: look inside an inductor and you will discover KVL is no longer working; look inside a capacitor and it's KCL that stops functioning.}

The only thing that exists are the electromagnetic fields, potential difference, and charge. Everything else is a simplified model of the consequences of those, useful in some circumstances, wrong in others.

That's not much of an exaggeration.

Unfortunately EM fields are my brain lock.

[nctnico]

Quantum computing.

That is largely mistified. A while ago I had a talk with somebody involved in quantum computing and the programming is pretty similar to what you'd do on a normal microprocessor. The only problem is that quantum computers don't have much logic to work with at this moment. There are simulated environments available like this one though: https://www.quantum-inspire.com/

[nctnico]

Ok, here's mine:  I can't remember numbers, names, or faces without a lot of effort.  I often can't recall the names of people whom I have known for years, it takes a lot of exposure to make a name stick.

Faces, images or written texts stick rather easily, but names need lots of repetitions before they stick. Sometimes indeed a bit embarrassing when you meet someone and have to guess their name.

Same here 

[tggzzz]

The answer is the h_FE is irrelevant to most BJT linear amplifier designs. I_C vs V_BE is what's important.

Nope. If you look at amplifier designs closely, you'll always see voltage to current conversion stages using resistors and other parts (like red LEDs) to cancel the temperature and process dependent Vbe changes / differences.

What I mean by changes in I_C  vs V_BE isn't process dependent variation, but ∆V_BE vs ∆I_C.

(1) que?
(2) you are missing the point: very few circuits make use of that dependence, whereas most circuits try to minimise its consequences

Take the common emitter amplifier for example. Note the A_V has nothing to do with h_FE.

So what?

[Siwastaja]

Math, especially once the big formulas come out. I understand the concept, but I just don't know how to start when it comes to applying it.  I tend to get hung up on what each variable represents, and what unit to use as often it's not really specified. Ex: if looking at a data sheet.

I have a similar problem. Especially when there are formulae with variables in lower and upper case, and Greek characters, which look similar to Latin ones. My hand wring is hard to read and slow, which doesn't help. I just about scraped through mathematics at college.

I couldn't agree more, and being the self-righteous asshole I am, I refuse to call this a brain lock of mine; I blame the math folks, they are just wrong. Mathematical notations, theory, and typical teaching material used would never pass modern day code review process. It's total obfuscation from day one, and especially difficult for people who "think aloud in their heads" like me, when we try to understand a new concept. You can't read out obfuscated formulae where a single letter which is pronounced exactly the same is stylized in three-four different visual ways, to denote completely different things, when all they had to do is to give variables descriptive names.

The tendency to not explain the variables at all (and not give a reference to page where they can be found) is totally inexcusable. It's sadism.

[Siwastaja]

After about 15 years, I've finally remembered which side of the diode symbol is "cathode" and which is "anode". 

While I quite often, on this forum and elsewhere, give expert-ish advice on lithium ion batteries, I have to Google every time which of the electrodes is anode and which cathode. It does not help the convention is reversed* compared to electrolytic or ultra capacitors. I just can't come up with a rule of thumb, I have to Google every time.

*) or is is? Or is my brain just too locked so that I think it is?

Diodes, somehow I don't have any trouble with. Maybe because I learned about them at age 9-10 or something like that. I guess it was early enough to stick. Batteries and electrolytic capacitors used (and still use) + and - in practical engineering, so the arbitrary "anode" and "cathode" naming only hinders the "look we are scientists!" LARP.

[IanB]

While I quite often, on this forum and elsewhere, give expert-ish advice on lithium ion batteries, I have to Google every time which of the electrodes is anode and which cathode. It does not help the convention is reversed* compared to electrolytic or ultra capacitors. I just can't come up with a rule of thumb, I have to Google every time.

That's because, as mentioned earlier in this thread, anode and cathode swap positions in a lithium ion cell depending on whether it is being charged or being discharged. When being charged the anode is the positive terminal, and when being discharged the anode is the negative terminal.

The rule of thumb was helpfully provided by Sredni. Conventional current in a circuit enters the anode and leaves the cathode.

[mkiijam]

To me the ANODE looks more like an "A" on the schematic. That's still my trick.