Question T5A02
From subelement T5 - T5A
Electrical power is measured in which of the following units?
Why is this correct?
Power is the rate at which electrical energy is used or generated, measured in watts (W). Volts measure voltage (electrical pressure), amperes measure current (electron flow), and watt-hours measure energy consumed over time. Only watts directly measure power itself - the instantaneous rate of energy conversion.
Memory tip
Remember that electrical quantities have distinct purposes: volts push, amperes flow, watts work. Power units always end in 'watts' - kilowatts, milliwatts, etc. When you see 'rate of energy use' think watts, just like miles per hour measures speed rate.
Learn more
In amateur radio operations, power measurements are crucial for station design and regulatory compliance. Your transmitter's output power rating determines your frequency privileges under Part 97. For example, Technician licensees are limited to specific power levels on HF bands. Understanding that watts measure power helps you calculate antenna system efficiency, determine proper feedline ratings, and ensure your station meets emission standards while maximizing effective radiated power within legal limits.
Think about it
Why do you think the FCC cares more about your transmitter's power output in watts than the voltage or current it draws from your power supply?