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The core circuit-theory calculations behind every electrical course, trade exam and bench measurement: Ohm's law, power, resistor…
Frequency-domain calculations for capacitors, inductors and RLC networks: reactance, impedance, resonance, time constants and…
Code-driven sizing of conductors, raceways, boxes and grounding for electricians and inspectors, based on NEC Article 250, 310…
Industrial and commercial power calculations: three-phase power, transformer sizing and ratios, motor currents, torque…
NEC Article 220 service and feeder load calculations plus overcurrent, fault-current and arc-flash sizing used on plan reviews…
Off-grid and standby power sizing: PV array and string design, battery banks, runtime, charge controllers, inverters and…
Bench and board-level design math for LEDs, op-amps, timers, PCB layout and radio work, used by electronics engineers, makers and…
Consumer and facility calculations that turn watts, hours and utility rates into dollars: appliance running costs, current…
Most used in electrical trade & electronics
- Ohm's Law CalculatorOhm's law and Joule's law (IEEE Std 280 quantity symbols)Pick the two quantities you already know — any two of voltage, current, resistance and power — and this calculator returns the…
- Electrical Power CalculatorIEEE Std 1459-2010 power quantity definitionsThis calculator separates the three numbers people routinely confuse: watts, volt-amperes and volt-amperes reactive. Give it a…
- Series Resistance CalculatorKirchhoff's voltage lawResistors end to end simply add: the total resistance of a series chain is the sum of its parts. This calculator takes up to…
- Parallel Resistance CalculatorKirchhoff's current lawEnter up to six resistor values and this calculator returns the equivalent resistance of the parallel combination, the current…
- Voltage Divider CalculatorKirchhoff's voltage law and Thévenin's theoremA two-resistor divider turns an input voltage into a smaller one, and this calculator gives you every number you need to use it…
- Capacitive Reactance CalculatorNEC 2023 Art. 460 · IEEE Std 18Enter a capacitance and a frequency and this calculator returns the capacitor's reactance in ohms, the current it draws from a…
- Inductive Reactance CalculatorSinusoidal steady-state AC theoryEnter an inductance and a frequency and this calculator returns the coil's reactance in ohms, the current it passes at a stated…
- RC Time Constant & Charge Time CalculatorFirst-order RC transient responseEnter a resistance and a capacitance and this calculator returns the time constant τ = RC , the capacitor voltage at any…
- Wire Size & Ampacity CalculatorNEC 2023 (NFPA 70), Table 310.16 with 110.14(C), 240.4 and 310.15Enter the load, the conductor material and the conditions the conductor will live in, and this calculator returns the smallest…
- Voltage Drop CalculatorNEC 2023 (NFPA 70) informational notes to 210.19 and 215.2Enter the load current, the one-way length of the run, the system voltage and the conductor you plan to use, and this…
- Conduit Fill CalculatorNEC 2023 (NFPA 70), Chapter 9 Tables 1, 4 and 5Enter the conduit you plan to use and the conductors you plan to pull, and this calculator returns the total conductor area…
- Three-Phase Power CalculatorBalanced three-phase AC power relations (IEEE Std 1459)Give this calculator the line-to-line voltage, the power factor, and any one of line current, kilowatts or kilovolt-amperes…