A zener diode works by utilizing the principle of the zener breakdown. This occurs when the reverse voltage applied to the diode reaches a certain threshold, causing a large increase in current flow through the diode. This breakdown voltage is known as the zener voltage and is a characteristic of each zener diode. The zener diode is designed to operate in this breakdown region, allowing it to maintain a constant voltage across its terminals, regardless of changes in the applied voltage.
The main purpose of a zener diode is to regulate voltage in electronic circuits. It is often used as a voltage reference or voltage stabilizer, providing a constant voltage output even when the input voltage varies. Zener diodes are also commonly used in voltage protection circuits, as they can quickly dissipate excess voltage and prevent damage to sensitive components.
While both types of diodes are made from semiconductor materials and allow current to flow in one direction, a regular diode is designed to operate in the forward bias region, while a zener diode operates in the reverse bias region. This allows a zener diode to maintain a constant voltage across its terminals, while a regular diode will experience a large increase in current flow when the forward voltage reaches a certain threshold.
In voltage regulation, the zener diode is placed in parallel with the load in a circuit. As the input voltage varies, the zener diode will maintain a constant voltage across its terminals, ensuring that the load receives a steady voltage. This is achieved by selecting a zener diode with a breakdown voltage that is slightly higher than the desired output voltage.
The main advantage of using a zener diode is its ability to provide a regulated voltage output, even when the input voltage varies. This makes it useful in a wide range of electronic circuits. However, zener diodes also have a limited power handling capability and can be prone to overheating if not properly used. They also have a higher cost compared to regular diodes. Additionally, zener diodes are only effective in regulating voltages above their breakdown voltage, making them unsuitable for lower voltage applications.