A fuller printable revision guide for voltage, current, resistance, power, and conductance with unit discipline, worked examples, and quick bench-side checks.
Use this guide when you need the core V-I-R-P-G relationships in a printable form that is still practical enough for bench checks, worksheet revision, and first-pass troubleshooting.
It is designed to support the online calculators, not replace them. The pack helps you decide which relationship to use, what the symbols mean, and what to sanity-check before trusting the number.
Volts, amps, ohms, watts, and siemens are the natural base units. Convert milli, micro, and kilo prefixes before combining values from different sources.
Most shocking answers in introductory circuit work are really prefix mistakes rather than algebra mistakes.
A 12 V drop at 2 A implies 6 ohms and 24 W dissipation. The resistance value solves the operating point, but the power value decides whether the component choice is realistic.
If V, I, and R are all recorded, check whether V really equals I x R. Any mismatch is a warning that the readings came from different points, different units, or a non-ohmic operating condition.
Keep this pack nearby for bench work, revision, and design reviews where the same small family of electrical relationships appears repeatedly and needs to stay readable under time pressure.
Solve for voltage, current, or resistance from any two values and validate all three when you already have a full set of measurements.
Solve power, voltage, or current from the other two values using the core electrical power relationships.
Use the Current from Power Calculator for practical circuit and electronics work involving current from power.
Use the Conductance Calculator for practical circuit and electronics work involving conductance.