FreeTools Labs Glossary
Electrical engineering basics
Learn how voltage, current, resistance and power relate, and how these relationships affect circuits and voltage drop.
Relevant tool
Electrical Engineering Calculator
Calculate Ohm's law, resistors, color codes and voltage drop.
Open Electrical Engineering Calculator →Electrical results relate voltage, current, resistance, power and energy, while network calculations depend on whether components are in series, parallel or part of an unloaded divider.
Functions and inputs
The calculator derives Ohm-law and power values from two known quantities, calculates series and parallel resistance, unloaded voltage dividers, conductor resistance and voltage drop, and decodes supported 4-, 5- and 6-band resistor colour codes.
Calculation model
The selected electrical mode uses Ohm's law, power, energy or the corresponding network relationship: U = R × I; P = U × I; E = P × t; Rseries = ΣR; Rparallel = 1 ÷ Σ(1/R).
How the calculator model works
Zero-division combinations are invalid rather than ordinary outputs. The conductor path uses the entered material model and doubles a one-way length for a return path; a voltage divider assumes no additional load across its second resistor.
Checked examples
This checked circuit example derives current first and then power from the same voltage and resistance: 12 V ÷ 6 Ω = 2 A; 12 V × 2 A = 24 W.
Units, display and interpretation
Read V, A, Ω, W and Wh as different electrical quantities; the visible fields follow the two-known-values mode or the selected resistor-code path: V · A · Ω · W · Wh; selected two-known-values path and supported resistor-colour bands.
Scope and limits
It does not select cable sizes or verify current capacity, fuses, protection, installation standards, temperature corrections, AC phase behaviour or real circuit safety. A numerical result is not installation approval.
Sources and foundations
SI Brochure — BIPM
Project basis for the units and prefixes used; the source is not retrieved at runtime.
IEC 60062:2016 einschließlich Korrigendum — IEC
Project basis for the supported interpretation of resistor colour codes.