That is the symbol for DC.
Both would work. I'd recommend the 7.5V. The on-board regulator will generate less heat when running compared to the 12V supply, meaning more current is available to your project.
That is the symbol for DC.
Both would work. I'd recommend the 7.5V. The on-board regulator will generate less heat when running compared to the 12V supply, meaning more current is available to your project.