Low Pass Filter voltage gain


Joined Jul 17, 2007
That is the entire point of a low-pass filter!
The low frequencies pass right through.
Frequencies above the passband edge (-3dB point) are attenuated more than 3dB.
It looks like the passband edge for this filter is at around 1200 to 1500 Hz.
Likely a Sallen-Key/Butterworth implementation.


Joined Feb 4, 2008
As SgtWookie said, a low pass filter pass the signals with low frequency and attenuates the signals with high frequency.

Also, a high pass filter pass high frequency signals and attenuates low frequency signals.

A band-pass filter passes signals with frequencies between a range and attenuates all the other

what is more, there are stop-band filters which attenuate the frequencies in a certain range and pass all the other.

just for information man.


Joined Dec 20, 2007
It is the result of the 10k resistor in series with the 15nF capacitor to ground in your other thread. It is a lowpass filter with a cutoff frequency (-3dB) at 1066Hz.


Joined Jan 28, 2005
The primary reason for the gain being a function of frequency is that the circuit appears to have a component whose impedance is a function of frequency. The most common components that have this characteristic are inductors or capacitors.