This tool calculates the dB (deciBel) equivalent of a voltage ratio.
- Input Voltage (Vin)
- Input Impedance (Rin)
- Output Voltages (Vout)
- Output Impedance (Rout)
PdB = 10*Log10((Vout2/Rout)/(Vin2/Rin))
If the output and input voltages are 2V and 1V, respectively, the dB equivalent of the ratio is 6 dB. This assumes the input and output impedance are the same.
When the output voltage is greater than the input, the dB value is positive (+) and it represents a gain.
When the output voltage is smaller than input, the dB value is negative (-) there’s a loss or attenuation.