Ask HN: What are some good resources to learn how electricity works?

Re:Ask HN: What are some good resources to learn how electri... by projektfu on Thursday June 18, 2020 @09:30AM (#23562899)

I remember in high school I had trouble getting it because I thought ohms law had too many variables. Then I realized that a 5V supply will always be 5V in normal operation and ohms law means the current varies.

All of the water analogies were unhelpful for me. I did better just doing the math and seeing the result.

Someone else mentioned MITx. I did that and it was revolutionary. I also have a pretty good book called Practical Electronics for Inventors.

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Re:Ask HN: What are some good resources to learn how electri... by samjohnson on Thursday June 18, 2020 @09:46AM (#23563036)

> Then I realized that a 5V supply will always be 5V in normal operation and ohms law means the current varies.

This is a great observation. I've often thought that teaching Ohms law as I=V/R would lead to less confusion. Similarly, in intro physics why is mass acceleration introduced as f=ma? Wouldn't a=f/m have a clearer meaning?

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Re:Ask HN: What are some good resources to learn how electri... by senderista on Thursday June 18, 2020 @10:46AM (#23563545)

I agree, that’s my preferred form as well. That’s because Ohm’s law is an empirical law, which states that current is proportional to voltage. It’s the definition of resistance, and it’s not always valid.

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Re:Ask HN: What are some good resources to learn how electri... by thehappypm on Thursday June 18, 2020 @09:57AM (#23563136)

Division is hard!

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Re:Ask HN: What are some good resources to learn how electri... by aphextron on Thursday June 18, 2020 @10:11AM (#23563271)

It becomes infinitely more clear and simple to understand when you stop thinking in terms of "A equals F divided by M" and think of it as "A equals the ratio of F to M".

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Re:Ask HN: What are some good resources to learn how electri... by tarlinian on Thursday June 18, 2020 @11:29AM (#23563984)

It also is infinitely more clear and simple to understand when you correctly realize that "F equals M times A" instead. I assume this was just an accidental transposition and you're not actually a crackpot. :)

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Re:Ask HN: What are some good resources to learn how electri... by aphextron on Thursday June 18, 2020 @11:57AM (#23564323)

Doh!

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Re:Ask HN: What are some good resources to learn how electri... by projektfu on Thursday June 18, 2020 @09:31AM (#23562917)

Also, don’t get hung up on electrons moving opposite the current. It’s not a big deal for most applications.

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Re:Ask HN: What are some good resources to learn how electri... by beamatronic on Thursday June 18, 2020 @11:22AM (#23563916)

> All of the water analogies were unhelpful for me

Same here, I just had to come to accept that there were orthogonal dimensions/measurements. It didn't matter if I understood them intuitively, as long as I worked with them orthogonally and in strict accordance with the basic equations.

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