Calculate resistor values for Pi attenuator circuits.
Design Requirements
Characteristic impedance (Ω)
Signal loss in Decibels (dB)
Component Values
R1 (Shunt)292.40 Ω× 2
R2 (Series)17.61 Ω× 1
Bill of Materials: You need two resistors of 292.4Ω and one resistor of 17.6Ω.
Nearest 5%
R1: 300.0Ω
Nearest 5%
R2: 18.0Ω
Overview
Pi attenuator reduces signal power while maintaining impedance match. Named for π (pi) shape. Used in RF circuits for signal level control. Resistor values depend on attenuation and impedance.
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Pro Tips
50Ω standard for RF systems.
3 dB attenuator = half power.
10 dB = 1/10 power; 20 dB = 1/100 power.
Use precision resistors for accurate attenuation.
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Fun Facts
"Pi and T attenuators are dual configurations."
"Minimum attenuation for 50Ω: 3 dB (R2 = Z0)."
"Power rating critical for high-power applications."
"Broadband: works from DC to GHz frequencies."
Formula: R1 = R3 = Z0 × (K+1)/(K-1); R2 = Z0 × (K²-1)/(2K) where K = 10^(dB/20)
