RF Attenuator Pad Calculator
Design a matched resistive attenuator. Pick a pi or T pad, the loss you need and the system impedance, and get the series and shunt resistors, the nearest 1% parts and the loss those parts really produce.
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Resistor values
| Element | Exact | Nearest E96 | Deviation |
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A pi pad puts one series arm between two shunt arms; a T pad puts one shunt arm between two series arms. The values are exact for a matched source and load at the chosen impedance, using K = 10^(dB/20) as the voltage ratio. The fitted column picks the closest 1% E96 value for each resistor, then reports the loss and the input match that combination actually gives, so a shortfall shows up before you solder. The model is an ideal resistive network: lead inductance, stray capacitance, resistor tolerance drift and power dissipation are not modelled, so choose parts rated for the power they will see and check the layout at high frequency. Everything is calculated in your browser; nothing is sent or stored.