using Uno as a chip programmer.

If I want to plug a brand new and out of the box Atmega, can I just plug it into Uno and program it then take it out and install it into a properly built circuit with clock and power and have it work?

Never Mind :slight_smile: Found an article that explains.

Unless the brand new ATMega has the bootloader already, this with swapping out chips will not work. You'll have to use the UNO as the ISP to program the new chip on a breadboard. If you can buy chips with the Optiboot bootloader already flashed in, your idea will in fact work. (Try Amazon for these chips)

A world of explanation in pictures: