LC filter for audio (Ratio L/C)


2006-09-08 2:04 pm
With a capacitor and an inductor, it isn't a 1st order filter, but a second order one.

Basically, the L/C ratio is the analogue of an impedance², which has to be compared with the load.

This sim shows the effect of an increasing L/C ratio, beginning with the green trace.

If you extrapolate to infinity, the circuit will become just a big inductance and a tiny capacitor, both having extremely high impedances at the frequency of interest, and allowing very little signal through, giving an extremely sharp peak.

This analysis neglects the Q of the reactive components themeselves.


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