Enter your Attenuator Type, System Impedance, Attenuation, Number of Steps, and Step Size into the Step Attenuator Calculator to find the resistor values R1 and R2 for each stage, along with your Total Attenuation, Input Impedance, and Output Impedance.
R1 (Series/Shunt)
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R2 (Shunt/Series)
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Total Attenuation
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Input Impedance
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Output Impedance
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Pi attenuators use a series resistor with two shunt resistors to ground. Tee attenuators use two series resistors with one shunt resistor. Bridged-Tee is a modified Pi topology that maintains impedance matching while providing attenuation.
Common system impedances are 50Ω for RF applications, 75Ω for video/cable systems, and 600Ω for audio applications. Match your attenuator impedance to your system's characteristic impedance.
While theoretically unlimited, practical single-stage attenuators are typically limited to 20-40dB due to resistor tolerance and parasitic effects. Higher attenuation usually requires multiple stages.
Smaller step sizes (0.5-1dB) provide finer control but require more switching positions. Larger steps (3-6dB) are simpler to implement but provide coarser adjustment. Choose based on your application's precision requirements.
For precise attenuation, use 1% or better tolerance resistors. Critical applications may require 0.1% precision resistors. Higher tolerance resistors can cause impedance mismatch and inaccurate attenuation values.
Yes, but parasitic capacitance and inductance become important at RF frequencies. Use low-inductance resistors, short connections, and consider transmission line effects above 100MHz.