Basic Qualification · B-005 Basic electronics and theory · B-005-008-007
La puissance de sortie d'un émetteur passe de 1 watt à 2 watts. Comment cette augmentation s'exprime-t-elle en décibels?
- A3 dB
- B10 dB
- C6 dB
- D1 dB
Correct answer: A — 3 dB. Question tirée de la banque officielle d'ISDE.
Why
Doubling the power from 1 watt to 2 watts represents a gain of exactly 3 decibels, a standard rule in radio physics where every time you multiply power by two, you add 3 dB to the level. The full explanation — and one for every question — is in Pro.
Practise this section
Basic electronics and theory is section B-005 of the Basic exam: The theory: Ohm's law, power, series and parallel circuits, AC and DC, frequency and wavelength, decibels, and the metric prefixes the exam leans on.
Drill B-005 — free, no account