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.
Section 10: Emergency and Standby Power Systems Bill Brown, P.E., Square D Engineering Services Introduction Emergency and standby power systems are designed to provide an alternate source of power if the normal source of power, most often the serving utility, should fail. As such, reliability of these types of systems is critical and good design practices are essential. Code and standards A.) Classification of emergency and standby power systems