You add a 9 dB gain amplifier to your 2-watt hand-held. What is the power output of the combination?

To solve this without a calculator, you can break the 9 dB gain down into three increments of 3 dB (3 dB + 3 dB + 3 dB = 9 dB). Remember the rule of thumb that every 3 dB increase means the power doubles. Starting with a 2-watt signal, the first 3 dB step doubles the power to 4 watts. The next 3 dB step doubles it again to 8 watts. The final 3 dB step doubles it a third time to 16 watts, making 16 watts the correct final output power. Distractors like 11 watts or 20 watts come from incorrectly adding the decibel value directly to the wattage, or misapplying simple multiplication rules instead of using sequential doubling.