Butterworth Pi LC Low Pass Filter Calculator

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Impedance Z0:
Number of Components: (1-11)
Inductance: Capacitance:
Unit : Unit :
L1: C1:
L2: C2:
L3: C3:
L4: C4:
L5: C5:

The Butterworth type filter was first described by the British engineer Stephen Butterworth.

A PI filter is a filter that has a series element and two parallel elements connected in the shape of the Greek letter PI.

Butterworth filter are characterized by a constant gain (flat response) across the midband of the circuit and a 20 dB per decade roll-off rate for each pole contained in the circuit.

Butterworth filters are termed maximally flat magnitude response filters, optimized for gain flatness in the pass band. The attenuation is -3db at cutoff frequency. Above the cutoff frequency the attenuation is -20 db.

The Butterworth is the only filter that maintains same shape for higher orders whereas other varieties of filters (Bessel, Chebyshev, elliptic) have different shapes at higher orders.

A Low pass filter is a filter that passes low-frequency signals but attenuates signals with frequencies higher than the cutoff frequency.