Electricity Calculator

  • Capacitor Energy Calculator
    Calculate the energy stored in a capacitor from its capacitance and voltage using E = ½ × C × V². Also shows stored charge Q = C × V.
  • Bridge Rectifier Calculator
    Calculate the DC output voltage and ripple voltage of a full-wave bridge rectifier from peak voltage, diode drop, load current, frequency, and filter capacitor.
  • Breaker Size Calculator
    Calculate the minimum circuit breaker amperage from load power and voltage, with the 1.25 continuous-load safety factor (US NEC 80% rule).
  • Boost Converter Calculator
    Calculate the output voltage of a boost (step-up) DC-DC converter from input voltage and duty cycle using Vout = Vin / (1 − D).
  • Watts to Amps Calculator
    Convert watts to amps for DC and single-phase AC circuits. Enter power, voltage and power factor to get current in amps instantly.
  • Watts to Lux Calculator
    Convert watts to lux using luminous efficacy and lit area. Enter power (W), efficacy (lm/W) and area (m²) to get illuminance in lux instantly.
  • Volt to Electron Volt Calculator
    Convert volts to electron volts instantly. Enter the voltage and charge (in elementary charges) to find energy in eV and joules with this free V to eV calculator.
  • Watt-hour Calculator
    Calculate energy in watt-hours (Wh) and kilowatt-hours (kWh) from power in watts and run time in hours. Free, instant Wh = P × t calculator.
  • Power Dissipation Calculator
    Calculate power dissipated in a resistor using P = I²R. Enter current in amperes and resistance in ohms to get power in watts instantly.
  • Internal Resistance Calculator
    Calculate a battery or cell's internal resistance from its EMF, terminal voltage, and current using r = (EMF − V) / I. Free, instant, accurate.
  • Faraday's Law Calculator
    Calculate the induced EMF in a coil using Faraday's law of electromagnetic induction from the number of turns, change in magnetic flux, and time.
  • Inductive Reactance Calculator
    Calculate inductive reactance (XL) in ohms from frequency and inductance using XL = 2πfL. Fast, accurate AC circuit calculator for engineers.
  • Electrical Power Calculator
    Calculate electrical power in watts from voltage, current and resistance. Uses P=V×I, P=I²×R and P=V²/R. Enter any two values to find power.
  • Drift Velocity Calculator
    Calculate the drift velocity of charge carriers from current, carrier density, cross-sectional area, and charge using vd = I / (n·A·q).
  • Cutoff Frequency Calculator
    Calculate the -3dB cutoff frequency of an RC filter from resistance and capacitance using fc = 1 / (2πRC). Free online tool.
  • Conductivity to Resistivity Calculator
    Convert electrical conductivity (S/m) to resistivity (Ω·m) instantly using ρ = 1/σ. Free online physics calculator with formula and worked example.
  • Capacitive Reactance Calculator
    Calculate capacitive reactance (Xc) in ohms from frequency and capacitance using Xc = 1 / (2π f C). Fast, accurate AC circuit tool.
  • Capacitance Calculator
    Calculate capacitance from charge and voltage using C = Q / V. Get results in farads and microfarads instantly with this free online tool.
  • AC Wattage Calculator
    Calculate AC real power (watts) from voltage, current and power factor using P = V × I × cos φ. Also shows apparent power in VA. Free and instant.
  • Spherical Capacitor Calculator
    Calculate the capacitance of a spherical capacitor from inner radius a, outer radius b, and dielectric permittivity εr. Get results in F, pF, nF and µF.
  • Resistor Thermal Noise Calculator
    Calculate Johnson–Nyquist thermal noise voltage of a resistor from resistance, temperature, and bandwidth. Get RMS noise in nV and nV/√Hz density.
  • Wire Resistance Calculator
    Calculate the electrical resistance of a wire from its resistivity, length, and cross-sectional area using R = ρL/A. Free online tool.
  • Voltage Divider Calculator
    Calculate the output voltage of a resistive voltage divider from Vin, R1 and R2. Also finds loop current and total power dissipated.
  • Wheatstone Bridge Calculator
    Calculate the unknown resistance Rx of a balanced Wheatstone bridge from R1, R2 and R3 using Rx = R2 × R3 / R1. Free, instant, accurate.

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