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Electrical & Electronics

Core circuit analysis tools, AC/DC component calculators, and conductor sizing utilities.

AC Power

Calculate active, reactive, and apparent power in single-phase AC circuits.

Battery Capacity

Determine the energy storage capacity and Ah rating for battery banks.

Battery Runtime

Calculate the expected operational time of a battery under a specific continuous load.

LED Resistor

Find the correct series resistor value to safely drive standard and high-power LEDs.

Ohm's Law Matrix

Universal solver for voltage, current, resistance, and power dissipation.

Parallel & Series Resistor

Calculate total equivalent resistance for complex resistor networks.

Power Factor

Calculate the ratio of real power to apparent power in an AC electrical system.

Resistor Color Code

Decode 4, 5, and 6-band through-hole resistor color values.

Three-Phase Power

Analyze voltage, current, and power in balanced 3-phase Delta and Wye systems.

Transformer

Calculate turns ratio, primary/secondary voltage, and current for ideal transformers.

Voltage Divider

Determine output voltage in a resistive divider circuit.

Voltage Drop

Calculate the loss of voltage over long cable runs due to internal wire resistance.

Wire Gauge (AWG)

Calculate wire diameter, cross-sectional area, and safe ampacity.

Electrical Engineering Calculators and Technical Tools

Electrical engineering calculations often require relationships between voltage, current, resistance, power, energy, and conductor characteristics. CelCalc provides a collection of practical electrical and electronics calculators for quick design checks, preliminary sizing, troubleshooting, and engineering reference. The tools cover common AC and DC circuit calculations as well as batteries, resistors, transformers, and cable sizing.

Circuit Analysis and Ohm's Law

Basic circuit analysis frequently starts with the relationship between voltage, current, and resistance. The Ohm's Law Matrix can be used to solve for voltage, current, resistance, or power when the required circuit quantities are known. The Voltage Divider calculator provides the output voltage of a resistive divider, while the Parallel & Series Resistor calculator determines equivalent resistance for common resistor arrangements.

AC Power and Three-Phase Systems

AC electrical systems require separate consideration of real power, reactive power, apparent power, and power factor. The AC Power calculator helps evaluate these quantities for single-phase circuits, while the Power Factor calculator relates real power to apparent power. For balanced three-phase systems, the Three-Phase Power calculator supports common Delta and Wye configurations and provides relationships between voltage, current, and power.

Batteries and Energy Storage

Battery calculations connect electrical load requirements with stored energy and operating time. The Battery Capacity calculator can be used to determine required ampere-hour capacity for a battery system, while the Battery Runtime calculator estimates operating time under a specified continuous electrical load. Real battery performance can differ from ideal calculations because of discharge rate, efficiency, temperature, battery age, and usable depth of discharge.

Resistors, LEDs, and Components

Component-level calculations are useful during circuit design and troubleshooting. The LED Resistor calculator determines a suitable series resistance from the supply voltage, LED forward voltage, and desired current. The Resistor Color Code calculator converts standard 4-band, 5-band, and 6-band resistor markings into resistance and tolerance values.

Wire Gauge and Voltage Drop

Conductor selection involves both electrical performance and thermal considerations. The Wire Gauge (AWG) calculator provides wire diameter and cross-sectional information together with an estimated ampacity, while the Voltage Drop calculator evaluates voltage loss caused by conductor resistance over a cable run. Actual cable selection should also consider installation method, ambient temperature, conductor material, insulation rating, grouping, allowable voltage drop, and applicable electrical codes.

Transformers and Electrical Conversion

An ideal transformer transfers electrical energy between primary and secondary circuits through electromagnetic induction. The Transformer calculator relates turns ratio, primary and secondary voltage, and current under ideal transformer assumptions. Practical transformers have additional losses, winding resistance, leakage reactance, magnetizing current, and thermal limitations that are not represented by an ideal calculation.

Engineering Use and Limitations

These calculators are intended for quick engineering calculations, preliminary design, education, and verification of hand calculations. They use simplified mathematical models appropriate to the stated inputs and assumptions. A calculator result should not be treated as a complete electrical safety or compliance assessment. Final designs may require additional analysis of fault current, protection devices, insulation, thermal limits, harmonics, grounding, electromagnetic compatibility, installation conditions, and applicable electrical standards.