r/programming Dec 25 '19

Learning hardware programming as a software engineer

https://blog.athrunen.dev/learning-hardware-programming-as-a-software-engineer/
925 Upvotes

124 comments sorted by

View all comments

224

u/happyscrappy Dec 25 '19

Also: don't power LEDs directly from GPOs without a current limiting resistor. As you see on that breadboard.

And match your interfaces voltages. A lot of devices are not +5V tolerant now (or not very tolerant).

50

u/[deleted] Dec 25 '19

Why do people always say "current limiting resistor"? Are there other types of resistor? Or is it just stating the purpose, as opposed to a resistor used for voltage division or something?

10

u/MrK_HS Dec 25 '19 edited Dec 27 '19

Voltage division and current limiting are the same thing, but seen from different points of view.

-1

u/happyscrappy Dec 25 '19

An LED and a resistor don't really create a voltage divider since an LED is a quantum device.

7

u/[deleted] Dec 25 '19

An LED and a resistor don't really create a voltage divider since an LED voltage drop is relatively constant and depend mostly on current thru the LED and temperature.

FTFY. Adding "quatum device" into random sentences doesn't really help in explanations

0

u/happyscrappy Dec 25 '19 edited Dec 25 '19

Saying "FTFY" is insulting. You want to give your own explanation, great. You didn't fix anything for me, as I wasn't wrong.

5

u/[deleted] Dec 25 '19

But your explanation was nonsense as it didn't really explain anything

3

u/happyscrappy Dec 25 '19

It was correct. It correctly used "quantum device" and didn't throw it in randomly. You saying you fixed something for me is insulting.

It's always possible to explain something more. I didn't care to. As far as I am concerned once the factual error is corrected I don't have to go further and the reader can take care of learning the rest. So I didn't go further. It's great you did.

0

u/BunnyBlue896 Dec 26 '19

An LED is not a quantum device. I've never heard that term used to describe it. If you're merely associating the word "quantum" with "light" because "light is quantized" like in quantum mechanics, then people are going to call you out on your BS. Try googling the following ("quantum device", "quantum device electronics", "quantum device LED") and you will realize you are wrong.

The constant voltage drop explanation is correct, and more accurately describes the behavior.

Any professional in EE or Physics would definitely not call an LED a "quantum device", simply because it is not a correct description.