RC Parallel Circuit Impedance Calculator

Find the total impedance, capacitive reactance, phase angle, and cutoff frequency of a parallel RC circuit from resistance R, capacitance C, and frequency f.

Input

Enter resistance R, capacitance C, and frequency f to compute the total impedance and phase of a parallel RC circuit.

Resistance R

Enter the resistance in ohms.

Capacitance C

Enter the capacitance in farads. Example: 0.0000001 equals 0.1 microfarads.

Frequency f

Enter the signal frequency in hertz.

Result

Total impedance |Z|

846.733016Ω

Angular frequency ω = 6,283.185307 rad/s

Capacitive reactance Xc

1,591.549431 Ω

Phase angle θ

-32.141908 deg

Power factor

0.846733

Cutoff frequency fc

1,591.549431 Hz

From the admittance Y = 1/R + jωC, the magnitude is |Z| = 1 / sqrt((1/R)² + (ωC)²) and the phase angle is θ = -atan(ωCR).

How it works

A parallel RC circuit uses admittance: 1/Z = 1/R + jωC, where ω = 2πf is the angular frequency.
The magnitude of the impedance is |Z| = 1 / sqrt((1/R)² + (ωC)²).
The capacitive reactance is Xc = 1 / (ωC), which decreases as frequency rises.
The phase angle is θ = -atan(ωCR); the current leads the voltage.
The cutoff frequency is fc = 1 / (2πRC), where the resistor and capacitor branch currents become equal.
All calculations use SI units (R in ohms, C in farads, f in hertz).

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