i want to connect thermal printer to arduino uno. my printer requre 5v and 1.5 amp current. can i connect it directly to uno 5v output pin
no way, thats too much current. 500ma max from usb
fixed, sorry misread question.
no im not connecting to i/o pin its 5v pin on uno board.
5V regulator is only good for ~800mA total.
USB power is only good for 500mA total.
You need an external source.
Be sure to connect your grounds together.