4 ms·

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 nor

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.

projektfu 6y ago
Also, don’t get hung up on electrons moving opposite the current. It’s not a big deal for most applications.
samjohnson 6y ago
> 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?
- thehappypm 6y ago
  Division is hard!
  - aphextron 6y ago
    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".
    - tarlinian 6y ago
      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. :)
      - aphextron 6y ago
        Doh!
- senderista 6y ago
  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.
beamatronic 6y ago
> 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.

projektfu 6y ago

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

samjohnson 6y ago

> 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?

thehappypm 6y ago
Division is hard!
- aphextron 6y ago
  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".
  - tarlinian 6y ago
    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. :)
    - aphextron 6y ago
      Doh!
senderista 6y ago
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.

beamatronic 6y ago

> 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.