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#electrical engineering basics

2 public questions tagged with this topic.

A \( 200 \, \Omega \) resistor and \( 15 \, \mu\text{F} \) capacitor are in series with a \( 220 \, \text{V} \), \( 50 \

**Capacitive reactance** X_C =1/(ω C)=1/(2π f C) (Ω), C capacitance (F), current leads voltage by 90°, I_rms = V_rms/X_C = V_rms ω C, I_peak = V_peak ω C, impedance Z = X_C for pure C. For 45 μF, 60 Hz, X_C=1/(2π×60×45×10⁻⁶)=58.9 Ω, V_rms=110 V, I_rms=1.867 A, I_peak=2.64 A. X_C = (1/ω C) = (1/314 × 15 × 10⁻⁶) ≈ 212.3 Ω . Z = √(200² + 212.3²) ≈ 291.5 Ω . RMS current: I = (V/Z) = (220/291.5) ≈ 0.755 A . Voltage across capacitor: V_C = I X_C = 0.755 × 212.3 ≈ 160.3 V . Applying X_L = ωL, X_C = 1/ωC, Z

Ref: NCERT > Physics Book > Alternating Currents > AC Through Capacitor - Capacitive Reactance

Why does the impedance of an AC circuit with only an inductor increase with frequency?

**LCR example** R=100 Ω, X_L=130 Ω, X_C=70 Ω, X_L-X_C=60 Ω, Z=√(100²+60²)=116.6 Ω, V_rms=300 V, I_rms=2.573 A, power P= I_rms² R =662 W? Actually P= V_rms I_rms cos φ, cos φ=R/Z=0.857, P=300×2.573×0.857=661.6 W, illustrating power factor. The impedance in a purely inductive circuit is the inductive reactance ( X_L = ω L ), where ω = 2π f . As frequency ( f ) increases, ω increases linearly, causing X_L (and thus impedance) to increase proportionally. Applying X_L = ωL, X_C = 1/ωC, Z = √(R² + (X_L - X_C)²), I_rms = V_rms/Z, P = V_rms I_rms cosφ, V_s/V_p = N_s/N_p, calculation gives Because indu

Ref: NCERT > Physics Book > Alternating Currents > LCR Series Circuit - Impedance and Phasor Diagram