• $summary_{type}$: application
• $word_{count}$: 160

A Zener diode operates in reverse breakdown where $V_Z$ remains nearly constant despite varying current. Circuit: input $V_{in}$ through series resistor $R_s$, Zener in reverse bias, load $R_L$ in parallel with Zener. Operation: $V_{out}$ = $V_Z$ (constant) as long as $I_Z$ > 0. Series current: $I_s$ = $\frac{V_in - V_Z}{R_s}$. Load current: $I_L$ = $\frac{V_Z}{R_L}$. Zener current: $I_Z$ = $I_s$ - $I_L$. Regulation holds when $I_Z$ remains positive. Maximum load current: I_L_{max} = $I_s$ (when $I_Z$ = 0), giving R_L_{min} = $\frac{V_Z}{I_s}$. For varying $V_{in}$: the Zener absorbs voltage fluctuations. If $V_{in}$ increases, $I_s$ increases, extra current flows through Zener, but $V_{out}$ stays at $V_Z$. JEE problems: (1) Find $I_Z$ for given $V_{in}$ and $R_L$. (2) Find $R_L$ range for regulation. (3) Find $R_s$ for desired regulation range. Key check: always verify $I_Z$ > 0.