To use this tool, enter the desired value of dB attenuation and the characteristic impedance (default value is 50 ohm). The tool computes resistor values in different configurations:

- Pi Attenuator
- T Attenuator

**Pi Attenuator Calculator**

**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 (to ground) 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**

**T Attenuator Calculator**

**Formula**

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

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

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

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