I would like to know what should happen when i connect low resistance to arduino output.
People say it will get damaged because it cannot supply the current. But I cannot understand this because the transistor can never exceed his max current.
Lets say, we can to drive the output low. This is done by activating typical one mosfet inside arduino pin. Schematic overview is shown here under. Rd is in this example 100 ohm.
After activating the transtor, it will conduct. The current that will flow can be found by using loadline.
The lower the resistor, the highter the slope of loadline, the more current will flow. BUT, if the resistor is very low, also the voltage over the RD will discrease and the current will not increase anymore because the transistor is in saturation. This means that the transistor will never exceed the maximum current? So very low resistance can be used on I/O to draw max current. It will just give the max possible current.
So can I connect 100 ohm to arduino I/O or not?
I also wonder, IOL = 20mA, and VOL= 0,9 in TABLE. But when I check that graph VOL is about 0.3-0.5 when IOL is 20mA. This is for arduino. Please check answers below