A Zener diode is a semiconductor device designed to operate in reverse bias by taking advantage of the Zener effect. It can regulate voltage in a circuit by maintaining a constant voltage drop when the reverse bias voltage exceeds the Zener voltage. The Zener diode symbol is drawn with an arrow representing forward bias current. It has applications in voltage regulation, signal clamping, voltage references, and overvoltage protection.

1. ZENER DIODE
Dr.B.A.Sapna
KIT-CBE

2. Introduction to Zener Diodes
A Zener diode is a highly doped semiconductor device specifically
designed to function in the reverse direction. It is engineered with a
wide range of Zener voltages (Vz), and certain types are even adjustable
to achieve variable voltage regulation.

3. What is a Zener Diode?
● A Zener diode is a special type of rectifying diode that can handle breakdown
due to reverse breakdown voltage without failing completely.
● Here we will discuss the concept of using diodes to regulate voltage drop
and how the Zener diode operates in reverse-bias mode to regulate voltage
in a circuit.

4. Zener Diode Symbol
The circuit diagram symbol used to represent a Zener diode is drawn
with an arrow, representing forward bias current

5. Zener Breakdown
● The PN junction is formed by the combination of the p-type and the n-type
semiconductor material. The combination of the P-type and N-type regions
creates the depletion region.
● The width of the depletion region depends on the doping of the P and N-type
semiconductor material. If the material is heavily doped, the width of the
depletion region becomes very thin.

6. ZENER EFFECT

7. Zener Diode Specifications
● Zener/Breakdown Voltage – The Zener or the reverse breakdown
voltage ranges from 2.4 V to 200 V, sometimes it can go up to 1
kV while the maximum for the surface-mounted device is 47 V.
● Current Iz (max) – It is the maximum current at the rated Zener
Voltage (Vz – 200μA to 200 A)

8. Zener Diode Circuits

9. Applications of Zener Diodes
● Voltage regulation
● Signal clamping
● Voltage reference
● Overvoltage protection

10. ADVANTAGES
● The Zener diode is less expensive than another diode
● This diode can be used in regulate and stabilize the voltage in a
circuit
● These diodes have a high-performance standard
● Control the flowing current
● Compatibility and obtainability

11. DISADVANTAGES
● Zener diode cancels out voltage by applying an even larger voltage in the
reverse direction wasting electricity in the process.
● A Zener diode has a relatively poor regulation ratio and is generally not as
good as the transistor.