• $summary_{type}$: revision
• $word_{count}$: 180

Essential formulas: $V_{rms}$ = $\frac{V_0}{sqrt}$(2). $X_L$ = omegaL. $X_C$ = $\frac{1}{omega*C}$. Z = sqrt($R^2$ + (X_{L-X}_C)^2). tan(phi) = $\frac{X_L-X_C}{R}$. cos(phi) = $\frac{R}{Z}$. P = VI*cos(phi) = $I^2$*R. $omega_0$ = 1/sqrt(LC). Q = $omega_0$L/R = $\frac{1}{R}$sqrt$\frac{L}{C}$. Bandwidth = $\frac{R}{L}$. Transformer: $V_s$/$V_p$ = $\frac{N_s}{N_p}$, $V_p$$I_p$ = $V_s$$I_s$.

JEE strategy: (1) Always convert to RMS before using power formulas. (2) Draw the impedance triangle — it immediately gives Z, phi, and cos(phi). (3) At resonance: Z = R, I = $\frac{V}{R}$, cos(phi) = 1 — check if the problem is at resonance first. (4) For transformer problems: first find turns ratio, then use power conservation. (5) Wattless current = I*sin(phi) — it flows but wastes no power. (6) $V_L$ and $V_C$ can exceed $V_{source}$ (voltage magnification by Q). (7) In parallel LC resonance, impedance is maximum (opposite of series). (8) Choke coil = inductor used to limit current without power loss.