Alternating Current, Circuits & Transformers Explained | Chapter 31 of University Physics
Alternating Current, Circuits & Transformers Explained | Chapter 31 of University Physics In Chapter 31, we explore alternating current (AC) fundamentals, from sinusoidal sources and phasors to reactive circuit elements, resonance, and the operation of transformers—key to power distribution and modern electronics. Watch the full video summary here for in-depth walkthroughs and phasor demonstrations. Phasors & Sinusoidal Sources AC voltages and currents vary as v(t) = V max cos(ωt) , where ω = 2πf . Phasors represent these sinusoids as rotating vectors in the complex plane, simplifying circuit analysis: RMS values: V rms = V max /√2 , I rms = I max /√2 US AC frequency: 60 Hz (ω ≈ 377 rad/s); Europe: 50 Hz (ω ≈ 314 rad/s). Resistance & Reactance Resistor (R): V R = I R , voltage and current in phase. Inductor (L): V L = I X L , X L = ωL , voltage leads current by 90°. Capacitor (C): V C = I X C , X C = 1/(ωC) , voltage lags current by...