Electricity Basics

Charge, circuits, voltage, and current — built from atoms up into the diagnostic mindset behind every repair: where, exactly, is this circuit open?

• 1.1What Is Electricity?What electricity physically is — at the level of atoms and charge — and how that becomes the idea of a circuit.BeginnerLow Risk20 min read
• 1.2Voltage — The Pressure of ElectronsWhy voltage only exists between two points, and what the numbers on a battery actually promise.BeginnerLow Risk25 min read
• 1.3Current — The Flow of ElectronsWhat current measures, which way it really flows, and why it — not voltage alone — is what makes electricity dangerous.BeginnerLow Risk20 min read
• 1.4Resistance — Opposition to FlowWhy every material fights current, how that fight becomes heat, and why resistance is the quantity a repair technician measures more than any other.BeginnerLow Risk20 min read
• 1.5Ohm's Law — The Foundation of Circuit AnalysisThe one equation that ties voltage, current, and resistance together — and the single most useful sentence a repair technician can carry to the bench.BeginnerLow Risk22 min read
• 1.6Power and Energy in DC CircuitsWhere the volts and amps finally turn into watts — the number on every rating label, the reason components run hot, and the quantity your electric bill is built from.BeginnerLow Risk22 min read
• 1.7Practical Measurement: Reading Voltage and CurrentThe chapter's payoff — picking up a multimeter and actually measuring the voltage and current you've spent six sections reasoning about, safely and correctly.BeginnerMedium Risk24 min read
• Chapter Quiz56questions · 80% required to continue