High Pass Filter Calculator

Calculate cutoff frequency and component values for RC, RL, and op-amp high pass filters

Calculate High Pass Filter Parameters

Filter Results

Calculated Values

Cutoff Frequency:N/A

Component Values for fc = 0 Hz

Required Resistance:N/A
Required Capacitance:N/A

Formula: fc = 1 / (2πRC)

Filter Type: RC High-Pass Filter

-3dB Point: At the cutoff frequency, the output is attenuated by 3dB (70.7% of input)

Filter Analysis

Example Calculation

Audio High-Pass Filter

Application: Remove low-frequency noise below 1 kHz

Resistance: 3.3 kΩ

Capacitance: 47 nF

Filter Type: RC High-Pass

Calculation

fc = 1 / (2π × R × C)

fc = 1 / (2π × 3.3×10³ × 47×10⁻⁹)

fc = 1.026 kHz

Filter Types

RC

RC High-Pass

Simple passive filter using resistor and capacitor

fc = 1/(2πRC)

RL

RL High-Pass

Resistor and inductor configuration

fc = R/(2πL)

OP

Op-Amp Filters

Active filters with adjustable gain

Inverting & Non-inverting

Design Tips

High-pass filters block low frequencies and pass high frequencies

Cutoff frequency is where output is -3dB (70.7% of input)

Higher order filters provide steeper roll-off

Op-amp filters can provide gain along with filtering

Understanding High Pass Filters

What is a High Pass Filter?

A high-pass filter is an electronic circuit that allows high-frequency signals to pass through while attenuating (reducing) low-frequency signals. It acts as the opposite of a low-pass filter, effectively blocking frequencies below a specified cutoff frequency.

Applications

  • Audio systems to remove low-frequency noise
  • DC blocking in AC-coupled amplifiers
  • Signal conditioning in data acquisition
  • Radio frequency communications

How It Works

RC High-Pass Filter

The capacitor blocks DC and low frequencies but allows high frequencies to pass. At high frequencies, the capacitor acts as a short circuit.

RL High-Pass Filter

The inductor opposes changes in current. High frequencies see high impedance through the inductor, forcing signals through the output resistor.

Op-Amp Filters

Active filters using operational amplifiers can provide gain while filtering, offering better performance and isolation.

Key Characteristics

Cutoff Frequency (fc): The frequency at which the output is -3dB relative to the passband
Roll-off Rate: First-order filters have -20dB/decade slope beyond cutoff
Phase Response: High-pass filters introduce phase lead at the cutoff frequency