RLC Circuit Calculator

An RLC circuit combines a resistor, an inductor, and a capacitor in an alternating-current network. Each component responds differently as frequency changes. Resistance dissipates electrical energy as heat and is independent of frequency in the ideal model. Inductive reactance rises with frequency according to XL = 2πfL, while capacitive reactance falls according to XC = 1 / (2πfC). Their competition determines the circuit impedance, phase relationship, and frequency response. For a series circuit, the same current passes through every component. The net reactance is XL minus XC, and the impedance magnitude is the square root of R squared plus the net reactance squared. A positive phase angle means the circuit is inductive and current lags voltage. A negative angle means it is capacitive and current leads voltage. The power factor is the cosine of this phase angle, so it approaches one when voltage and current align. For a parallel circuit, every branch shares the same voltage. Conductance and susceptance are therefore added as admittance before the reciprocal is taken to obtain impedance. This calculator assumes ideal components connected as three parallel branches. Real inductors have winding resistance, capacitors have equivalent series resistance, and both may vary with temperature and frequency, so laboratory measurements can differ from an ideal result. Resonance occurs when inductive and capacitive reactance cancel. The ideal resonant frequency is 1 / (2π times the square root of LC), and it does not depend on resistance. At series resonance, impedance reaches its minimum and current reaches its maximum. At parallel resonance, ideal branch currents cancel and total impedance reaches its maximum. Resonance is central to radio tuning, filters, oscillators, matching networks, and frequency-selective sensors. Use consistent units when comparing results. This tool accepts inductance in millihenries and capacitance in microfarads, then converts both to SI units internally. Frequency is entered in hertz and resistance in ohms. The results are suitable for coursework, initial design, and checking hand calculations. For safety-critical or high-frequency hardware, include component tolerances, parasitic effects, voltage ratings, current ratings, and measured frequency response in the final engineering analysis.