DC (Direct Current): In a DC circuit the voltage is constant, so the current flows steadily in one direction. The electron flow is unidirectional, and Ohm’s Law (\( V = IR \)) directly governs the behavior of the circuit.
AC (Alternating Current): In an AC circuit the voltage varies sinusoidally with time, causing the current to alternate its direction periodically. The effective voltage at any moment is given by \( V_{\mathrm{eff}} = V_0 \sin(2\pi f t) \), where \( V_0 \) is the amplitude and \( f \) is the frequency.
Components:
Battery: Supplies the driving voltage (DC or AC amplitude).
Resistor: Limits current and drops voltage (\( V = IR \)).
Capacitor: Stores energy in an electric field; its capacitive reactance \( X_C = \frac{1}{2\pi f C} \) determines its behavior in AC circuits.
Inductor: Stores energy in a magnetic field; its inductive reactance \( X_L = 2\pi f L \) affects current in AC circuits.
Ammeter: Measures current; in AC circuits it shows RMS or instantaneous values.