A Pi Pad attenuator is one in which the resistors are in a **π** configuration. The shunt resistors (R1) are connected to ground, while the series resistor (R2) is connected between them.

This forms a Pi Network.

Enter the desired value of attenuation and the characteristic impedance (default value is 50 ohm).

**Formula**

**R _{1} = Z_{o} [10^{dB/20} + 1] / [10^{dB/20} – 1]**

**R _{2} = Z_{o}/2 [10^{dB/10} – 1] / [10^{dB/20}]**

where **R1** is the shunt resistor and **R2** is the series resistor. To build this attenuator you will need

**two shunt resistors**– one at the input and the other at the output**one series resistor**

Note that it is assumed that both the source and load resistance are equal in this calculation.

## References

[1] Pi Pad Attenuator on Wikipedia