Electricity 1 — DC Circuits
Ohm’s law, series & parallel circuits, the voltage divider, real energy costs, and RC charging.
Three quantities run everything electrical: voltage (the push, V), current (the flow, A) and resistance (the squeeze, Ω). Ohm’s law ties them together, and nearly everything else is bookkeeping on top of it.
- 01 Ohm’s law & power I = V/R: double the push, double the flow; double the squeeze, half the flow. Power — how fast electrical energy becomes heat or light — is P = V·I.
- 02 Series & parallel Series resistors stack: the current squeezes through both, so resistances ADD. Parallel resistors share: the current has two paths, so the combined resistance…
- 03 The voltage divider Two resistors in series split the supply voltage in proportion to their resistance — the single most used sub-circuit in electronics (volume knobs, sensor…
- 04 What electricity costs Your meter bills energy, not power: kilowatt-HOURS. A power times a time is an energy — the engine carries the units through.
- 05 Capacitors — charging up A capacitor is a small bucket for charge. Through a resistor it fills not linearly but exponentially: fast at first, ever slower. The time constant τ = R·C…
next course: Electricity 2 — AC Circuits →