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.
A voltage transformer takes the 220-240 volt electricity supplied by the outlet, and changes it to 110-120 volts for use by the appliance. (For a Type C or Type E European outlet, you would also need to attach a plug adapter, our item #EA9C or EA9, to the voltage transformer's plug, so that the transformer can plug into the British outlet.)