What is an undesirable characteristic of a Zener diode?

A Zener diode is designed to maintain a constant voltage across it when reverse-biased, operating in breakdown region, which is useful in voltage regulation applications. However, one of the undesirable characteristics of a Zener diode is its extreme sensitivity to temperature changes. As the temperature varies, the breakdown voltage can shift significantly, leading to instability and inaccurate voltage regulation.

Temperature effects can cause the Zener voltage to either increase or decrease, resulting in suboptimal performance. This sensitivity necessitates careful thermal management in applications where the surrounding temperature fluctuates, as even small temperature variations can impact the diode's performance.

In contrast, a Zener diode typically has high resistance when it is reverse-biased, which is actually a beneficial characteristic for most applications. While moderate current draw might be typical during operation, it isn’t particularly detrimental like the extreme temperature sensitivity can be. Thus, focusing on the characteristic of extreme sensitivity to temperature changes highlights a critical consideration in the practical deployment of Zener diodes in electronic circuits.