Task: Text Categorization
Input (English): Transferred electron devices are a form of these components that utilize negative differential resistance and are generally named for Gunn. A law giving their current is named for transistor-inventor William Shockley. One of these and a MOSFET is used to form a synchronous rectifier, and four of these devices are arranged in a namesake bridge in full-wave rectifiers. If these have a large enough negative voltage drop, they go into breakdown, though reverse-bias operation is possible in their Zener variety. For 10 points, name these devices that normally consist of a p-n junction and only allow current to pass in one direction, and which also come in light-emitting types.
Output (English): Science