PC Accessories

How Does a Keyboard Work?


A keyboard is one of the most important hardware parts of a computer. One cannot imagine using a PC without having a keyboard. Using a keyboard is very easy; you can type anything with simple key taps. However, you might be wondering what converts those key presses into actual words because there’s actually a lot going on at the back end.

Quick Answer

A keyboard consists of a large number of pressable keys. It connects through your computer via a cable or Bluetooth. Under the keys, different insulating and conducting layers are placed on top of each other. When you press a key, the conductive layers are pressed together, generating an electrical signal that shows up as a letter on your screen.

Apart from this basic structure, there are also LED lights on some keyboards for keys like Num Lock and Caps Lock. Many keyboards also have a backlit layer under the keys.

The following article lets you know a lot more about how a keyboard works. So, let’s dive right into the depths of a physical keyboard.

Keyboard Types

PC keyboards can sometimes differ depending on the number of keys they carry. Many manufacturers produce their own version; however, the basic keys remain the same. There are around 80 to 110 keycaps on a regular keyboard. 

Almost all modern keyboards follow the QWERTY pattern, and the keys are basically divided into four categories.

  • Typing keys.
  • Function keys.
  • Control keys.
  • Numeric keys or a numeric pad.
Did You Know?

The QWERTY pad was designed for typewriters because, using the normal ABC format, some frequently used keys got very closely placed. It caused the typewriters to jam. The QWERTY arrangement placed those keys far apart, so the typing speed could get a little slower for smoother operation.

Inside the Keyboard

It might seem like your keyboard is a simple device, but there’s much complexity on the inside. A keyboard can be seen as a mini-computer because it has its own motherboard, key matrix, and microprocessor

The matrix joins all the keys to the motherboard network. The motherboard circuit is closed everywhere except below the keys. There’s a hole below every key that keeps the circuit open. You can see it for yourself by popping out some keys from your keyboard.

You will see a hole between a rectangular bar that holds the key, and a small rubber will be at the end of this hole. It springs back the keys to their original position when pressed.

Under the Keys

You can remove the top portion of your keyboard to observe the circuit matrix below. There will be transparent layers with conductive circuit channels and circular nodes at each key’s place. 

Most keyboards also have an LED circuit board at the top right corner. These LEDs will light up when you turn on the Caps Lock, Scroll Lock, or Num Lock. If your keyboard supports RGB backlighting, there will also be an RGB strip below the keys.

You will notice that all the circuit lines will converge at a single spot on your keyboard. This is where the USB port from your keyboard will be connected to the PC.

Circuit Formation

There are two sheets of conducting circuits below your keyboard. These two sheets are kept separate by another transparent sheet while there are circular cutouts below the keys on your keyboard.

The circuits from the conducting sheets have only a small separa\tion between them at these spots. The circuit is completed when you press a key, generating an electric signal. 

Signals Into Words

When the signal is generated, the microprocessor on your keyboard identifies which key has been pressed. A character map stored in its ROM helps the processor in this task. It also identifies whether you have pressed a single key or a key combination and displays the result accordingly.

This feature enables the processor to identify capital letters, characters, and commands like copy, paste, and cut.

When you press a key, it also creates a vibration known as a bounce. This bounce is ignored if you perform a single tap. However, if you press and hold a key, a series of bounces is generated, counted as a continuous press. 

Laptop Keyboard

Laptop keyboards are a little different from regular PC keyboards. Because a laptop has much less space than a computer, it has to cram all the circuitry into that closed space.

Laptop keyboard keys do not protrude as much. They are essentially flat, and if you pop them out, you can see that the rubber springs keeping them in place are also placed very close to the keycaps.

The circuit layers work the same way as a regular keyboard; however, the layers are made thinner to fit inside a laptop easily.

The Bottom Line

It’s hard to imagine a PC properly working without a keyboard as it is one of the most important pieces of hardware. There are approximately 100 keycaps on a regular keyboard having a network of circuitry beneath them. There are small openings below the keys where these circuits are open.

The circuit closes when you press a key, and an electric signal is sent to the keyboard’s processor. It identifies which key is being pressed and displays it on the screen. All these processes happen within a fraction of a second, making the keyboard no less of a wonder. We hope this article has helped you completely understand the working of a computer.

Frequently Asked Questions

Why is a keyboard considered an input device?

An input device provides some data to the computer for processing. A keyboard provides the computer with words as data and doesn’t receive any output. So, it is considered an input device.

How many keys are there on a keyboard?

Most widely used keyboards have exactly 101 keys or keycaps. However, this number varies greatly depending on the manufacturer of the keyboard. The number of keys on a keyboard ranges from 80 to 110.

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