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# Pi-Section Attenuator

The table in Figure below lists resistor values for the Π attenuator matching a 50 Ω source/ load at some common attenuation levels. The resistors corresponding to other attenuation levels may be calculated from the equations.

Formulas for Π-section attenuator resistors, given K, the voltage attenuation ratio, and ZI = ZO = 50 Ω.

The above apply to the π-attenuator below.

What resistor values would be required for both the Π attenuators for 10 dB of attenuation matching a 50 Ω source and load?

10 dB Π-section attenuator example for matching a 50 Ω source and load.

The 10 dB corresponds to a voltage attenuation ratio of K=3.16 in the next to last line of the above table. Transfer the resistor values in that line to the resistors on the schematic diagram in Figure above.

Last Update: 2010-11-19