SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/ham-power-13-8v-10a

How much power is delivered by 13.8 volts DC at 10 amperes?

138 watts, because power equals voltage times current.

  1. 23.8 watts
  2. 0.7 watts
  3. 138 watts ✔

Why: Power in watts equals volts times amps, P = I x E. Multiply 13.8 volts by 10 amps and you get 138 watts.

Huh, didn't know that: A typical 50-watt mobile FM radio needs a 13.8-volt supply rated at about 12 amperes.

The dad joke
Watt did the power supply say to the radio? I've got your back, 13.8 volts of it.
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Sources

  1. NCVEC 2026-2030 Technician Question Pool (Feb 19, 2026 release) https://www.ncvec.org/downloads/2026-2030%20Technician%20Pool%20and%20Syllabus%20Public%20Release%20Feb%2019%202026.pdf

Test yourself in the game

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