lukitusnäppäin

A lukitusnäppäin, often translated as a lock key or toggle key, is a modifier key on computer keyboards that, when pressed, locks a certain keyboard state on. Unlike keys like Shift or Ctrl which only modify the behavior of other keys while they are held down, a lock key's effect persists after the key is released. The most common examples are Caps Lock, Num Lock, and Scroll Lock.

Caps Lock, when activated, causes all alphabetic characters to be typed in uppercase. Pressing Caps Lock again typically deactivates the state. Num Lock enables the numeric keypad to function as a set of number keys and arithmetic operators, rather than navigation keys like arrow keys or Home/End. Scroll Lock, though its functionality is less commonly used in modern applications, historically affected how scrolling occurred in applications, often by locking the scroll behavior to keep a particular cell or area visible.

The presence and function of lock keys can vary slightly between operating systems and keyboard layouts. Indicator lights on the keyboard often visually signal when a lock key is active. These keys are essential for efficient typing and data entry, allowing users to switch between different input modes without continuously holding down a modifier key.