ZENER DIODES posses numerous applications in transistor circuitary. Here we are going to discuss some important points in Zener diode applications. → Zener Diode Shunt Regulator Zener diode is popularly used as Shunt Regulator or Voltage Regulator. Voltage regulation is a measure of circuit's ability to maintain constant output voltage even when either input voltage or load current varies. Figure shows a Zener diode is connected as voltage regulator. It may provide a constant voltage from a Source whose voltage may vary appreciably. A current limiting resistor Rs is connected serial to Zener diode, it is necessary in the circuit to limit the current in safe value. The voltage source Vs and resistor Rs is so selected such that the Zener diode operates in breakdown region. The diode voltage in this region, which is also the voltage across the load Rl is called Zener voltage, Vz and the diode current is called Zener current, Iz. The series resistor Rs absorbs the output voltage fluctu...