RC Low Pass Filter

Since capacitive reactance decreases with frequency, the RC circuit shown discriminates against high frequencies. The circuit is an AC voltage divider with an output which falls off at high frequencies at the rate of 6 dB per octave.

Calculation 计算

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RC Low Pass Filter Details

RC Low Pass Filter Calculation

Since capacitive reactance decreases with frequency, the RC circuit shown discriminates against high frequencies. The circuit is an AC voltage divider with an output which falls off at high frequencies at the rate of 6 dB per octave.

More detail 更多内容

One approach to the design of a low-pass filter is to establish a frequency "breakpoint" or "knee" by choice of the resistance and capacitance. The design calculation works by clicking on the desired quantity in the expression. Enter the necessary data and then click on the quantity you wish to calculate. Default values will be entered for unspecified quantities, but all quantities may be changed. After the filter has been designed, the amount of attenuation in decibels at any frequency can be evaluated by the separate calculation below. Once you get well above the breakpoint frequency, the amount of attenuation will increase by about 6dB per octave, which you can confirm with that exploratory calculation.

For R = x10^ Ω = kΩ = MΩ 对于 R = x10^ Ω = kΩ = MΩ 中文译文中的待填/计算数值依次对应：1：rb 2：rp 3：rk 4：rm。实际数值以上方原输入框为准。

and C = x10^ F = 以及 C = x10^ F = 中文译文中的待填/计算数值依次对应：1：cb 2：cp 3：cm。实际数值以上方原输入框为准。

= pF 电容结果：= pF（皮法） 中文译文中的待填/计算数值依次对应：1：cpf。实际数值以上方原输入框为准。

the breakpoint angular frequency ω = x10^ rad/s 转折角频率 ω = x10^ rad/s 中文译文中的待填/计算数值依次对应：1：wb 2：wp。实际数值以上方原输入框为准。

and frequency = x10^ Hz = kHz = MHz

and the capacitive reactance at the breakpoint is

并在断点处的电容电抗是

XC = x10^ ohms = kohms = Megohms 容抗 X C = x10^ 欧姆 = 千欧 = 兆欧 中文译文中的待填/计算数值依次对应：1：xb 2：xp 3：xk 4：xm。实际数值以上方原输入框为准。

Evaluation of filter action:

If the input angular frequency ωin = x10^ rad/s 如果输入的角频率 ω_in = x10^ rad/s 中文译文中的待填/计算数值依次对应：1：wib 2：wip。实际数值以上方原输入框为准。

the output ratio Vout/Vin = x10^ = dB. 输出比 V_out / V_in = 10^x = dB。 中文译文中的待填/计算数值依次对应：1：vvb 2：vvp 3：vdb。实际数值以上方原输入框为准。

滤波器作用的评估：