A low pass filter is a type of filter circuit that is used to attenuate frequencies above a cut-off frequency fC.
They consist of a resistor and capacitor in series, with the output taken across the capacitor.
![Low pass filter circuit diagram.](https://electronicsreference.com/wp-content/uploads/2021/03/image-17.png)
The following calculators are designed to aid in the design and understanding of low pass filters.
There are three calculators on this page:
1) Low pass filter cut-off frequency calculator
2) Low pass filter capacitor selection calculator
3) Low pass filter resistor selection calculator
Low Pass Filter Cut-Off Frequency Calculator
The low pass filter cut-off frequency calculator can be used to calculate the cut-off frequency. Two inputs are required: (1) the resistance of R1, and (2) the capacitance of C1. Based on these values, the calculator will provide the cut-off frequency.
The mathematical formula for the cut-off frequency in terms of the resistance of R1 and capacitance of C1 is given by:
f_C = \frac{1}{2 \pi R_1 C_1}
Low Pass Filter Capacitor Selection Calculator
The low pass filter capacitor calculator can be used to calculate the value of capacitor needed to create a filter with a specific cut-off frequency.
It requires two inputs: (1) the desired cut-off frequency, and (2) the resistance of R1.
The mathematical relation for the capacitance of C1 in terms of the cut-off frequency fC and resistance of R1 is given by:
C_1 = \frac{1}{2 \pi f_C R_1}
Low Pass Filter Resistor Selection Calculator
The low pass filter capacitor calculator can be used to calculate the value of resistor needed to create a filter with a specific cut-off frequency.
It requires two inputs: (1) the desired cut-off frequency, and (2) the capacitance of C1.
The mathematical relation for the resistance of R1 in terms of the cut-off frequency fC and capacitance of C1 is given by:
R_1 = \frac{1}{2 \pi f_C C_1}
If these calculators didn’t help, check out our other calculators for electronics or our comprehensive tutorials!