An array is a special variable, which can hold more than one value at a time. If you have a list of items (a list of car names, for example), storing the cars in single variables could look like this:
milliamps or watt/volt. The SI base unit for electric current is the ampere. 1 ampere is equal to 1000 milliamps, or 1 watt/volt. Note that rounding errors may occur, so always check the results. Use this page to learn how to convert between milliamperes and watts/volt. Type in your own numbers in the form to convert the units!
Second, you need to know the volts flowing through the wires. Volts are a measure of the pressure that causes current to flow through a circuit. Generally, household wiring is 120 or 240 volts. To determine the amount of wattage a branch circuit can handle, multiply the circuit's amperage by the circuit's volts. A 20-amp, 120-volt circuit can handle 2,400 watts. The following list gives you the average wattage rating for common household equipment.