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# Math Prefixes for Electrical Measures

The 2022-2026 Technician License question pool inquires about those pesky math prefixes used in front of many electrical measurement quantities:

T5B03: Which is equal to one kilovolt?

A. One one-thousandth of a volt

B. One hundred volts

C. One thousand volts

D. One million volts

These types of Technician questions boil down to interpreting the prefix that’s added to the unit. In this case the unit is the electrical measure of electromotive force (EMF), volts. The prefix kilo has been added to the unit volts in the question. These kinds of mathematical prefixes are essentially multipliers, but you have to know by how much to multiply for a given prefix. Here is a list of the most common mathematical prefixes you’ll find in ham radio:

 Math Prefix Multiplier Numerical Value Decimal Value pico one trillionth 1/1,000,000,000,000 0.000000000001 nano one billionth 1/1,000,000,000 0.000000001 micro one millionth 1/1,000,000 0.000001 milli one thousandth 1/1,000 0.001 ​ unity (one), no multiplier ​ 1 kilo one thousand 1,000 ​ mega one million 1,000,000 ​ giga one billion 1,000,000,000 ​

The prefix kilo means 1,000. So, a kilovolt is 1,000 volts. The correct answer to question T5B03, "Which is equal to one kilovolt?" is C. One thousand volts.

Converting Between Prefixes: You should also know that when converting between these prefixed units, the decimal point in a provided value shifts three positions for each “step” in the list of prefixes above. If you are stepping from a smaller prefix to a larger prefix (ex: converting from volts to kilovolts), move the decimal three positions left for each step. Conversely, if you are stepping from a larger prefix to a smaller one (ex: converting from microfarads to nanofarads), move the decimal three positions right for each step.

-- Stu WØSTU

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