What is the difference between Pi, Tee, and Bridged-Tee attenuators?
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. See also our Antenna Downtilt Calculator.
How do I choose the right system impedance for my attenuator?
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.
What is the maximum practical attenuation for a single stage?
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.
How does step size affect attenuator design?
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.
What resistor tolerances should I use for accurate attenuation?
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.