I have multiple chinese copies of the nano board and on each one of them the A0 and A1 pins seem to produce current much lower than expected when measured with a multimeter but the voltage is not changed.
I'm only trying to power LEDs and I'm using the pins as digital outputs.
Is this normal on all arduino nanos? Or are all of my nano copies defective?
It's strange.
Even if the LED Vf is estimated to be 1.2V (quite low), 77mA will not flow. (5V - 1.2V) / 220Ω ≈ 17.3mA
Also, 77mA from the pin is clearly excess current.
Oh right so I'm measuring the current directly from pin to ground without the led so like there is very minimal resistance. my apologies for not mentioning that.
Did you use pinMode() to correctly change the pin to output?
If it is true, they have similar output drivers except A6 and A7, so I think the internal driver for that pin is simply broken.
I did indeed. I'm not sure how the same 2 pins have broken drivers on all 10 boards I have but I guess I got unlucky with a bad batch sold separately or something. Good to hear that the original isn't supposed to exhibit similar behavior.
Oh btw can you point me to an article that says that using a multimeter between a pin and ground is bad? I haven't been able to find any info on that doing a quick search. And not to doubt your expertise or anything but I would like to read on the topic more and have a source to refer back to.
There are an infinite number of mistakes that you can make in electronics. Do you really expect to find an infinite number of articles warning you about them?