This converter makes it possible to transform an effective voltage (Vrms) applied to a load of known resistance into power expressed in dBm. It is particularly useful for electronics and RF engineers who want to know the relative power of a signal from its voltage.
Formula
P(W) = V rms 2 / R
dBm = 10 × log 10 (P(W) × 1000) = 20 × log 10 (V rms ) + 30 − 10 × log 10 (R)
Explanation of the formula
The first step calculates the wattage from the rms voltage and impedance of the load. Then this power is converted to dBm using the decimal logarithm and multiplying it by 1000 to go from watts to milliwatts. The final formula simplifies the direct calculation from Vrms and R to obtain dBm.
Uses
- Evaluate the power of RF signals from the measured voltage.
- Convert generator or amplifier voltages to relative power levels.
- Assist in the design and testing of audio and RF circuits.
- Provide a convenient power measurement for comparison or technical documentation.