What are the two main categories of semiconductor diodes?

The two main categories of semiconductor diodes are indeed junction diodes and point contact diodes.

Junction diodes are the most common type, formed by joining two different types of semiconductor material, typically p-type and n-type, creating a p-n junction. This structure allows for the control of current flow, making it essential in numerous electronic applications, including rectification and signal modulation.

Point contact diodes are an earlier form of diode that uses a small piece of semiconductor material (usually germanium) in contact with a fine wire or metal point. This type of diode is less common in modern applications and is typically used in older technologies or specific niche applications.

Understanding these categories is crucial for anyone working in electronics, as the type of diode chosen impacts the functionality and efficiency of circuits in which they are implemented. The other options provide different categorizations that do not specifically apply to semiconductor diodes as the primary distinguishing features.