RLC Notch Filter Circuit

RLC Notch Filter

An RLC notch filter rejects a narrow band by providing a low-impedance shunt path at its tuned frequency. In this example, the inductor and capacitor are in series from the signal node to ground. At their resonant frequency the branch draws signal away from the output load; above and below that point its impedance rises. The input resistor limits loading and helps define the depth and width of the notch. This is a useful diagram for explaining unwanted tone suppression and interference rejection. Real notch depth depends on component Q, tolerances, source impedance, and load impedance, so prototype or simulate a design before relying on the ideal response.

類型 電路圖標準 IEEE Std 315 / ANSI Y32.2引擎 schematex-circuit更新時間 2026/9/24

需求

“Draw an RLC notch filter with a 1 V AC input, 1 kΩ series resistor, a 10 mH and 100 nF series shunt branch, a 50 Ω loss resistor, and a 10 kΩ output load.”

接著試試Change the tank capacitor to 47 nF.Add a test point at the output.

這張圖裡有什麼

看懂背後的決策。

01Notch branch

Put a series L-C path from signal to ground.

02Isolation

Use a series resistor ahead of the output.

03Load

Include the next-stage input resistance.

Use to illustrate a tuned branch that attenuates one narrow frequency region.

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常見問題

What does a notch filter remove?

It attenuates a selected narrow frequency band while passing frequencies on either side.

Why is the L-C branch in series?

A series L-C branch has low impedance at resonance and can shunt that frequency to ground.

What limits notch depth?

Component losses, source resistance, and load impedance keep a practical notch from being ideal.