be80be
Well-Known Member
There a lot of people would have you to think that the ATmega328P can source and sink 40mA. a pin
First off it's Absolute Maximum Rating is 40mA but this is basically a one pin per port, Not all 23 I/O
And the chip can only sink or source 200mA from gnd and VCC
A port can only sink or source 100mA
What this means is don't use more then a port can output when figuring you hardware
Like if you need to drive a relay use a 2n3904 or a 2n7000 with base or gate resistors and a kickback diode
Light a led use a resistor need more power use a driver 2n3904 or a 2n7000 for small loads up to 200mA and look up better options for bigger loads.
First off it's Absolute Maximum Rating is 40mA but this is basically a one pin per port, Not all 23 I/O
And the chip can only sink or source 200mA from gnd and VCC
A port can only sink or source 100mA
What this means is don't use more then a port can output when figuring you hardware
Like if you need to drive a relay use a 2n3904 or a 2n7000 with base or gate resistors and a kickback diode
Light a led use a resistor need more power use a driver 2n3904 or a 2n7000 for small loads up to 200mA and look up better options for bigger loads.