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.
120 and 240 Volts. The power delivered to your home is 120 or 240 volts. That means it's the standard voltage as measured at the transformer outside your home. Nominal voltage can vary up to plus or minus 5 percent from its stated definition.