A Pi attenuator is a resistive network used to reduce signal power while maintaining impedance matching. It consists of a series resistor (R1) between input and output, with two shunt resistors (R2) to ground.
Simple schematic:
Input ---- R1 ---- Output
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R2 R2
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GND GND
Enter the desired attenuation in dB and the system impedance (typically 50 Ω for RF). The calculator will compute the required resistor values.