This calculator determines the resistor values needed to design a bridged T-attenuator, ensuring accurate attenuation while maintaining constant impedance at the input and output.
It is particularly useful for RF engineers and lab technicians working on signal level reduction, impedance matching, or device testing without introducing unwanted reflections.
Formulas
R1 (Ω) = Z0 × [10^(dB/20) − 1]
R2 (Ω) = Z0 / [10^(dB/20) − 1]
Explanation of formulas
- R1 is the series resistance between the source and the load.
- R2 is the branch resistance in the bridged T network.
- Z0 corresponds to the characteristic impedance of the system, generally 50 Ω.
- The attenuation factor in decibels (dB) defines the desired signal reduction.
Bridged T-attenuator for 10 dB and 50 ohms
Input : Attenuation = 10 dB, Z0 = 50 Ω
Exit :
- R1 ≈ 40.82 Ω
- R2 ≈ 61.35 Ω
Benefits and uses
- Ensures constant impedance matching across the entire band.
- Ideal for reducing signal levels in RF testing.
- Suitable for balanced and unbalanced systems.
- Easy to integrate into mitigation and filtering networks.