Interesting video, though I do think it would benefit in discussing the intuition that it shouldn't matter (ideal vs real world circuits). At ~1:30, you show sourcing vs sinking with a microcontroller. Intuition (in ideal circuits) would suggest that there should be no difference, as current is still passing through the same path regardless of where the load happens to be placed. It would be nice to show the non-ideal / real world factors and characteristics that cause VCC drop. Perhaps a simple demo with an oscilloscope would be nice. It doesn't have to be long; just show the basic circuit, show how it triggers a rush of current, and show the oscilloscope. You're already doing that, sorta, with the animation, but maybe glossed over a little quick (at least imo). Thanks for the vids!
hmmm at first the idea confuses me because in all cases, current flows through both the load and the microcontroller. what if i say that whether or not the IC is sinking or sourcing depends on the relative position (in the circuit) of the IC and load with respect to VCC and ground? VCC -> load -> IC -> ground : IC is sinking VCC -> IC -> load -> ground : IC is sourcing and lets say we want to use the microcontroller to drive a DC motor through a transistor (to amplify the signal). Is the microcontroller sinking or sourcing in this case?
That is correct, it does depend on the relative position of the load and the IC. I think your breakdown is correct and a good way to think of it. And in regards to the microcontroller driving a transistor to drive a DC motor, it is *sourcing* in this case, because it is providing the current to the transistor. Even if it's a MOSFET (which ideally won't use current but will in reality because of gate capacitances), it is still the MCU sourcing.
I'm a little bit confused. Are you saying that it is better to put an LED between VCC and the pin, inverting the logic, rather than the usuall way of connecting the LED between pin and ground?
Yep, exactly! I didn't like this idea at first - it hurt my "high is on, low is off" way of thinking, but then I started noticing that it's pretty common to put the LED between VCC and the GPIO. Finally, I learned why. In many cases, it won't make that big of a difference (or any at all) but, from all I've read and learned, it is best practice to use the MCU as a sink for an LED, not a source.
I got my Associates in EET last year and have been struggling to find a job. Are there any resources for either side projects or self employment ideas at this level?
