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Pi Attenuator Calculator

  Calculates the resistor values, attenuation, 'impedance', reflection coefficient, VSWR and return loss of a Pi attenuator. This can be built into a FLEXI-BOX and a transmission line PCB is available which easily adapts for this circuit with one simple trimming operation. There is also a selection of suitable RF connectors available.

[pi attenuator formula]

  1) Enter the system impedance and required attenuation then then press "Calculate" below to obtain the Ideal resistor values.

System impedance:   Ohms
Required attenuation:   dB
Ideal series resistor:   Ohms
Ideal shunt resistor:   Ohms


  2) Change the calculated resistor values in the amber text boxes below to the nearest Preferred Resistor Values or to those available then press " Calculate" below to get the resulting attenuator parameters.

Preferred series resistor:   Ohms
Preferred shunt resistor:   Ohms
Mismatch Losses:  Included
Attenuation:   dB
Input Impedance:   Ohms
Reflection Coefficient: 
Return Loss:   dB

This calculator uses JavaScript and will function in most modern browsers. For more information see About our calculators

The calculator uses simple Ohms law calculations, and more comprehensive equations for Voltage Reflection Coefficient and VSWR which are available at:-

This calculator is provided free by Chemandy Electronics in order to promote the FLEXI-BOX

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Mismatch Losses added on 31/12/2012