1. Characteristics of a Zener Diode: A Zener diode is designed to operate in the "Reverse Breakdown" region. Once the reverse voltage reaches a specific threshold called the Zener Voltage ($V_Z$), the diode starts conducting current heavily.
2. Voltage Regulation: In this breakdown region, the voltage across the Zener diode remains remarkably constant even if the current flowing through it changes significantly. This flat V-I characteristic in the reverse region makes it act like a constant voltage source.
3. Comparison with other devices:
• FET/MOSFET: These typically behave more like voltage-controlled
current sources in their saturation regions.
• SCR: A Silicon Controlled Rectifier is a switching device (ON/OFF); it does not maintain a specific constant voltage level across its terminals while conducting in the same regulated way as a Zener.
Due to its ability to maintain $V_Z$ across a wide range of currents, the Zener diode is the primary component used for simple voltage regulation.