To calculate the change in temperature, subtract the initial temperature from the final temperature. Example: 84.2 degree Fahrenheit - 41 degrees Fahrenheit = 43.2 degrees Fahrenheit. The temperature from morning to afternoon changed by 43.2 degrees Fahrenheit.
It needs 12 volts so it will be the standard modern power supply provides 12 volts of power.
Electric Power in the USA. Electric power is standardized in all states across the USA. It is set at 110 Volts and 60 cycles. 220 Volt power is used in homes only for large appliances like stoves, water heaters and clothes dryers. It is not normally available for personal appliances. Standard electric plugs, as illustrated at the top of this page, have two flat blades.