Input Devices

This lesson covers the main input devices required by the OCR H446 specification. For each device, you must understand how it works, what it is used for, and its advantages and disadvantages.

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What Is an Input Device?

An input device is any hardware that allows a user (or the environment) to enter data or instructions into a computer system. The data is converted into a digital form the computer can process.

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Keyboard

How It Works

Type	Mechanism
Membrane keyboard	A pressure pad under each key completes a circuit when pressed. Cheaper, quieter, less tactile
Mechanical keyboard	Each key has an individual switch mechanism. When pressed, the switch closes a circuit. More tactile, more durable
Capacitive keyboard	Pressing a key changes the capacitance of a circuit beneath it. No physical contact needed. Used in some premium keyboards