What does the rule of 3’s state in terms of dB changes and power?

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What does the rule of 3’s state in terms of dB changes and power?

The rule of 3's relates decibels to power: a change of +3 dB doubles the power, while a change of -3 dB halves the power. This comes from the power ratio formula P2/P1 = 10^(ΔdB/10). With ΔdB = +3, P2/P1 = 10^0.3 ≈ 2, so power doubles. With ΔdB = -3, P2/P1 = 10^(-0.3) ≈ 0.5, so power is halved. Note this is about power, not voltage; at the same impedance, a +3 dB change in voltage would correspond to a voltage increase of about √2, not a doubling.

The rule of 3's relates decibels to power: a change of +3 dB doubles the power, while a change of -3 dB halves the power. This comes from the power ratio formula P2/P1 = 10^(ΔdB/10). With ΔdB = +3, P2/P1 = 10^0.3 ≈ 2, so power doubles. With ΔdB = -3, P2/P1 = 10^(-0.3) ≈ 0.5, so power is halved. Note this is about power, not voltage; at the same impedance, a +3 dB change in voltage would correspond to a voltage increase of about √2, not a doubling.

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