for my project (LED lights) I need a 12V power supply. I also plan to power arduino uno board with the same voltage through the connector. My question is, a few threads here mention 12V to be a "limit" voltage and potentially needing a heatsink. I only plan to use the Arduino for SPI control of the LED stripe plus powering one temperature sensor + an LED. So I guess that the current draw @5V is not going to be more than 200mA. Would this be OK for a 24/7 operation?
Also, if not, is there any point on using a simple voltage divider (maybe down to 8V) to burn off the excess energy and "help out" the regulator? If so, what would be the most appropriate resistor sizes?