The relationship between volt-amperes (VA) and watts represents a fundamental concept in electrical power. Voltamperes measure the apparent power in an alternating current (AC) circuit, which is the product of the voltage and current. Watts, on the other hand, measure the real power, indicating the actual power consumed by a load and performing work. For example, a device rated at 100 VA might consume less than 100 watts due to power factor considerations.
Understanding the distinction between these two power measurements is critical for electrical system design and equipment selection. Proper sizing of power sources, such as generators and uninterruptible power supplies (UPS), requires accurate assessment of both apparent and real power demands. Historically, neglecting the difference between VA and watts has led to inefficiencies, equipment failures, and increased energy costs. Consideration of power factor, the ratio between watts and VA, is therefore essential for optimization.