High Pass Filter Calculator
Calculate capacitor value for RC high pass filters
Hertz (Hz)
Ohms (Ω)
How to Use This Calculator
Enter Cutoff Frequency
Enter the desired cutoff frequency (3dB point) in hertz. Frequencies above this pass through.
Enter Resistance
Enter the resistor value in ohms. This forms the RC filter with the capacitor.
Get Capacitor Value
Click calculate to see the required capacitor value for the high pass filter.
Formula
fc = 1 / (2π × R × C)
C = 1 / (2π × R × fc)
Where:
- fc = Cutoff frequency (Hz)
- R = Resistance (Ω)
- C = Capacitance (F)
- π ≈ 3.14159
Example:
Cutoff Frequency = 1000 Hz, Resistance = 1000 Ω
C = 1 / (2 × π × 1000 × 1000) = 1 / 6,283,185 = 0.159 µF
About High Pass Filter Calculator
The High Pass Filter Calculator helps design RC high pass filters. High pass filters allow frequencies above the cutoff to pass while attenuating lower frequencies. They're commonly used in audio circuits, AC coupling, and signal processing.
When to Use This Calculator
- Audio Circuits: Design filters to remove low-frequency noise
- AC Coupling: Calculate coupling capacitors for amplifiers
- Signal Processing: Design filters for specific frequency ranges
- Educational Purposes: Learn about filter design
Why Use Our Calculator?
- ✅ Accurate Calculations: Uses correct filter formula
- ✅ Easy to Use: Simple interface
- ✅ Free Tool: No registration required
- ✅ Educational: Includes formulas and examples
Common Applications
Audio Amplifiers: High pass filters remove DC offset and low-frequency noise from audio signals, improving signal quality.
AC Coupling: Capacitors in amplifier circuits act as high pass filters, blocking DC while passing AC signals.
Tips for Accurate Results
- Enter frequency in hertz
- Enter resistance in ohms
- Cutoff frequency is the -3dB point
- Higher frequencies require smaller capacitors
Frequently Asked Questions
What is a high pass filter?
A high pass filter allows frequencies above the cutoff frequency to pass through while attenuating frequencies below the cutoff. It's the opposite of a low pass filter.
What is the cutoff frequency?
The cutoff frequency (fc) is the frequency at which the filter's output is -3dB (approximately 70.7%) of the input. It's the boundary between passband and stopband.
How does it differ from low pass?
High pass filters pass high frequencies and block low frequencies. Low pass filters do the opposite - they pass low frequencies and block high frequencies.