How Does a Keyboard Send Information to the Computer?
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A Look Inside the Keyboard
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Each keyboard uses a series of switches to provide messages to the computer. The keys are nested on rubber dome switches that contain carbon in the center. This causes each key to be pressed down and come right back up when you do not press it anymore. Keyboards contain anywhere between 80 to 110 keys, but there could be more. The keyboard also has a microprocessor, to restrict the frequency with which signals are passed. Regardless of how sophisticated your keyboard is, keyboards generally use the same system for transmitting signals to the computers that they are attached to.
What Happens When You Press a Key
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When a key is pressed, the rubber dome switch pushes down on the circuit board, making its center carbon contact touch the circuit, completing an electrical circuit. This instructs the keyboard to send a signal. Signals from the keyboard continue to be sent at a certain frequency, regulated by the microprocessor, as the key continues being held down. That is why, when you hold down a key, the computer repeats the letter, number or symbol on the screen as long as the key is pressed down.
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Where Does a Keyboard Get Its Power?
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Keyboards have internal circuit boards, meaning it must pull power from somewhere. Whether a keyboard uses a USB cable or a PS/2 cable, when the computer detects a keyboard connected, it will supply power to the keyboard through the cable. Wireless keyboards work differently in that they are powered by an internal battery. The wireless portal is powered by the computer, and a signal is shared between the two devices, using infrared, radio or Bluetooth technology. However, wireless keyboards are similar to wired keyboards in that they both have a similar structure, sending signals when a circuit is completed on their circuit boards. The only difference is how the signal reaches its destination.
Different Keyboard Layouts
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Keyboards generally have different layouts. The most common layout in use today is the QWERTY layout, used in keyboards in North America, among other regions. However, other layouts do exist as well. For example, keyboards in Europe sometimes use the AZERTY layout or the QWERTZ layout. Primarily, these layouts are named for the first five alphabetic keys on the keyboard layout.
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