Final answer:
A Zener diode exhibits a negative temperature coefficient, meaning that as the temperature increases, the breakdown voltage of the Zener diode decreases. This behavior is useful in voltage regulation applications.
Step-by-step explanation:
A Zener diode is a type of diode that is designed to operate in the reverse breakdown region, where it exhibits a negative temperature coefficient. This means that as the temperature increases, the breakdown voltage of the Zener diode decreases. The negative temperature coefficient is due to the increase in the number of charge carriers at higher temperatures, which reduces the resistance of the diode and allows more current to flow.
This behavior is useful in voltage regulation applications. When a Zener diode is connected in reverse bias, it maintains a constant voltage across its terminals, regardless of changes in temperature or current. This makes it suitable for providing a stable reference voltage or for protecting sensitive components from voltage spikes.
For example, let's say we have a Zener diode with a breakdown voltage of 5V. As the temperature increases, the breakdown voltage may decrease to 4V. This means that even if the input voltage decreases or increases, the output voltage across the Zener diode will remain stable at 4V.