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dBm, watts & volts
Convert absolute level to power and RMS voltage.
HB3YAQ · Ajdin HadzicLearning to take awayhttps://hb3yaq.ch/en/tools/dbm
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Formula & context
P[W] = 10^((dBm − 30)/10); Uᵣₘₛ = √(P · R)
0 dBm equals 1 mW. Voltage depends on load resistance. The result is RMS voltage across a resistive load, not a generator’s open-circuit voltage.
A worked example
0 dBm into 50 Ω gives 1 mW and approximately 0.2236 V RMS.
Assumptions & limits
Complex impedances or non-sinusoidal signals require additional treatment. The peak-to-peak result assumes a sine wave.
dB, dBm and powerUnderstand the reasoning →From reading to experimenting
dBm, watts & volts
0 dBm into 50 Ω gives 1 mW and approximately 0.2236 V RMS.
Open example with starting values →Level: 0 dBm · Resistive load: 50 ΩBack to the learning article →Then change exactly one value. Compare the result and use the formula to explain why it changes. The model limits below the calculator also apply here.