RLC Impedance & Phase Angle Calculator

RLC Impedance & Phase Angle Calculator | Online Free Tool | Elysia Tools

Tool usage guide

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Category: Math & Numbers
Input types: select, number, checkbox
Output type: json
Sample coverage: 4
API ready: Yes

Overview

The RLC Impedance & Phase Angle Calculator computes the complex impedance, magnitude, and phase angle for series or parallel AC circuits containing any combination of resistors, inductors, and capacitors. It calculates inductive and capacitive reactances based on your operating frequency and supports linear frequency sweeps to analyze circuit behavior across a range of frequencies.

When to use

When designing or analyzing AC circuits containing resistors, inductors, or capacitors in series or parallel configurations.
When you need to determine the phase shift or power factor angle between voltage and current at a specific operating frequency.
When plotting or analyzing the frequency response of an RLC filter or resonant circuit using a linear frequency sweep.

How it works

1Select the circuit topology (series or parallel) and input the values for resistance (R), inductance (L), and capacitance (C).
2Specify the operating frequency, or enable the frequency sweep option by entering the start frequency, end frequency, and number of sweep points.
3The calculator computes the inductive reactance (X_L = 2πfL) and capacitive reactance (X_C = 1/(2πfC)) for each frequency point.
4It combines these reactances with the resistance to output the complex impedance (Z), magnitude (|Z|), and phase angle (φ) in a structured JSON format.

Use cases

Calculating the input impedance and phase shift of a passive crossover network for audio speakers.
Simulating the frequency response of a bandpass filter to determine its bandwidth and cutoff frequencies.
Determining the impedance matching requirements for RF antennas or AC power distribution systems.

Examples

1. Analyzing a Series RLC Circuit at Power Line Frequency

Electrical Engineering Student

Background

A student is analyzing a series RLC circuit in a lab experiment to verify theoretical calculations at a standard power line frequency of 50 Hz.

Problem

Calculate the total impedance and phase angle of a series circuit with a 100 Ω resistor, a 0.1 H inductor, and a 10 µF capacitor.

How to use

Set the topology to 'series', enter 100 for R, 0.1 for L, 0.00001 for C, and 50 for the frequency. Keep the frequency sweep disabled.

{
  "topology": "series",
  "R": 100,
  "L": 0.1,
  "C": 0.00001,
  "frequency": 50,
  "sweepEnable": false
}

Outcome

The calculator outputs a total impedance magnitude of approximately 303.82 Ω and a phase angle of -70.78°, indicating a capacitive dominant circuit.

2. Frequency Sweep of a Parallel RLC Circuit

Hardware Design Engineer

Background

An engineer is designing a parallel RLC tank circuit and needs to observe how the impedance changes across a frequency range from 50 Hz to 200 Hz.

Problem

Determine the impedance magnitude and phase angle at 4 discrete frequency points to locate the resonance region.

FAQ

Can I calculate the impedance of a circuit with only a resistor and a capacitor?

Yes, you can omit any component. The calculator supports any subset of R, L, and C.

What is the difference between series and parallel topology in the calculations?

Series topology adds impedances directly (Z = R + j(X_L - X_C)), while parallel topology adds admittances (1/Z = 1/R + 1/(jX_L) + jX_C).

How does the frequency sweep feature work?

When enabled, the calculator evaluates the circuit's impedance at multiple evenly spaced frequency points between your specified start and end frequencies.

What units should I use for the component values?

Use Ohms (Ω) for resistance, Henries (H) for inductance, Farads (F) for capacitance, and Hertz (Hz) for frequency.

Does this calculator provide the resonant frequency of the circuit?

It does not explicitly output the resonant frequency, but you can identify it by finding the frequency where the phase angle is zero or the impedance magnitude reaches its minimum or maximum.

{
  "topology": "parallel",
  "R": 100,
  "L": 0.05,
  "C": 0.0001,
  "frequency": 100,
  "sweepEnable": true,
  "sweepStart": 50,
  "sweepEnd": 200,
  "sweepPoints": 4
}

Run this tool

Examples that match this tool

Continue with connected tools and hubs

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Analyzing a Series RLC Circuit at Power Line Frequency

2. Frequency Sweep of a Parallel RLC Circuit

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