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2nd Order High Pass Filter Equation:
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A 2nd order high pass filter is an electronic circuit that attenuates signals with frequencies lower than the cutoff frequency while allowing higher frequencies to pass. It's called "2nd order" because it has two reactive components (typically one inductor and one capacitor) that create a 12 dB/octave roll-off.
The calculator uses the following equation:
Where:
Explanation: The cutoff frequency is the point where the output signal is attenuated by 3 dB from the passband level.
Details: The cutoff frequency determines which frequency components of a signal will be attenuated and which will pass through the filter. Proper selection of L and C values is crucial for achieving the desired frequency response.
Tips: Enter the inductance in Henries and capacitance in Farads. Both values must be positive numbers. The calculator will compute the cutoff frequency where the filter begins to attenuate the input signal.
Q1: What's the difference between 1st and 2nd order filters?
A: 1st order filters have a 6 dB/octave roll-off while 2nd order filters have 12 dB/octave, providing steeper attenuation outside the passband.
Q2: How do I choose L and C values?
A: Start with standard component values near your desired cutoff frequency, then adjust based on availability and other design constraints.
Q3: What are typical applications of high pass filters?
A: Used in audio systems to block DC offset, in RF systems to remove low-frequency noise, and in many signal processing applications.
Q4: Does component tolerance affect the cutoff frequency?
A: Yes, real components have tolerances (typically 1-20%) that will affect the actual cutoff frequency.
Q5: Can I cascade two 1st order filters to get a 2nd order response?
A: Yes, but the resulting filter characteristics will be different from a true 2nd order filter unless properly designed.