Watts, volts and amperes have a simple relationship with many interesting ramifications for electrical engineering. Voltage is a measure of potential difference between two electrical conductors, an ampere is a rate of flow of electrons, and a watt is a unit of electrical work that is done. The equation is simply that the watts are equivalent to the volts times the amps: W = V * A. This equation,
. the most basic in electrical engineering, has several additional ramifications. It means that one can calculate the amperes with A = W / V, and, similarly, calculate the volts with V = W / A.In household appliances, since the voltage supplied by the power company is a regional standard (120 volts in the United States), a wattage rating is really a measure of how much current the machine draws. This is important when dealing with household circuits; each circuit may tolerate only so many amperes of current, and overshooting this number with too many appliances may lead to tripped circuit breakers or blown fuses. Anyone dealing with batteries, particularly car batteries, must also consider this equation when adding additional wiring; a battery is only able to supply a certain amount of current at one time.Ohm's Law also gives several additional equations with which to work. Since the amperes are the voltage divided by the resistance in ohms, A = V / R, it is possible to calculate watts when knowing only two of these variables; the equations are W = (V^2) / R and W = (A^2) * R. Several other equations also come from this relationship between watts, volts, amperes and ohms, which allow people to know any two of these variables from the other two. Knowing these equations by heart is a fundamental skill for anyone involved in the field of electrical engineering or design.
