Capacitors, Inductors & Reactance
Every capacitors, inductors & reactance calculator on CalcEngines — unit converters, derived indices and interpretive tools, each with its formula, a worked example and the reference intervals it is judged against.
9 calculators in this section
- Air-Core Inductor Calculator (Single-Layer Coil)Inductance of a single-layer air-cored coil from its diameter, length and turns by Wheeler's 1928 formula — or the turns for an inductance you want — with Nagaoka's exact coefficient beside it so you can see what the rule of thumb costs, plus wire length, DC resistance and Q.
- Capacitive and Inductive Reactance CalculatorReactance of a capacitor or an inductor at any frequency — X_C = 1/(2πfC), X_L = 2πfL — with the current it allows at a stated voltage, the 90° phase shift, and the net reactance when both are in series.
- Capacitor Energy and Backup Time CalculatorEnergy stored in a capacitor in joules, watt-hours and milliamp-hours — and the question people actually arrive with: how long it holds a load up between Vₘₐₓ and Vₘᵢₙ at constant current, constant power or constant resistance, or how much capacitance a required hold-up needs.
- Capacitor Ripple Current and ESR CalculatorWhat ripple current does to an electrolytic: the power its ESR dissipates, the core temperature that produces, the three parts of the ripple voltage and which of them dominates at your frequency, and the expected life that follows from the Arrhenius ten-degree rule. This is why a capacitor that meets the voltage spec still fails in two years.
- Capacitor Self-Resonance CalculatorEvery capacitor is a series R-L-C, and above its self-resonant frequency it is an inductor. This gives the resonance, the impedance at the frequency you care about and whether the part is capacitive, resistive or inductive there — and then the anti-resonance between two paralleled capacitors, where the combination is worse than either one alone.
- LC Resonant Frequency CalculatorResonant frequency of an LC tank from the inductance and capacitance — or the capacitor you need for a frequency you already have — with the characteristic impedance, Q, bandwidth and the frequency band your component tolerances really allow.
- MLCC DC Bias Derating CalculatorWhat is left of a ceramic capacitor once the DC bias, the temperature, the ageing and the tolerance have all taken their share — and then the part that matters: how far that moves your filter's corner frequency and how many decibels of attenuation it costs you at every frequency above it.
- RC and RL Time Constant CalculatorThe time constant τ of a resistor-capacitor or resistor-inductor circuit, how far it has charged or discharged after each τ, the time to reach any percentage, and the voltage and current at any moment, with the charging curve drawn from 0 to 5τ.
- Tantalum Capacitor Derating CalculatorTantalums fail short and a shorted one in a low-impedance circuit can ignite, and every published tantalum design rule follows from that. Voltage derating, the series resistance rule in ohms per applied volt, the turn-on surge current, the category voltage above 85 °C, and what changes when the cathode is a conductive polymer instead of manganese dioxide.