Definition
A unit of apparent electrical power, calculated by multiplying voltage by current (volts × amperes) in an alternating current (AC) circuit. Volt-amperes (VA) measure the total power flowing in a circuit, including both the real power that does work and the reactive power that does not.
Plain English
A way of measuring electrical power in AC systems by multiplying volts by amps. Unlike watts, which measure only useful work being done, volt-amperes measure the total electrical load the system has to handle.
Context Anchor
Seen in aircraft electrical-system work, especially when checking generator, alternator, inverter, transformer, or equipment load ratings.
Derivation
A direct combination of the two units being multiplied: 'volt' (named after Alessandro Volta, who invented the battery) and 'ampere' (named after André-Marie Ampère, who studied electric current). The term simply names the math: volts times amperes.
Why Pilots Care
AC generators and inverters in aircraft are rated in volt-amperes, not watts, because they have to supply the full apparent load — not just the useful portion. Understanding VA helps when interpreting electrical system capacity and avoiding overload.
Intuition Check
Do not assume volt-amperes always mean the same thing as watts. In some circuits they may be equal, but in alternating-current systems volt-amperes describe the load the source must supply, while watts describe useful power used.
Example Sentence 1
The aircraft's inverter is rated at 250 volt-amperes, which limits how much AC equipment can be powered at one time.
Example Sentence 2
During the inspection the technician confirmed the inverter output stayed within its rated volt-amperes.