HARDWARE ( CS ) Flashcards
What is meant by an input device?
Input devices transfer data from the outside world to the computer.
List examples of input devices.
- Keyboards
- Mice
- Digital cameras
- Games controllers
- Microphones
What are the stages of how computer systems work?
- Input devices put data into the system
- The data is processed
- The processed data may be saved using primary or secondary storage
- Output devices send data from the computer to the user
How does a key on a keyboard function?
A key is made from plastic with a peg that fits into a hole, and a rubber piece makes it bounce back up.
What happens when a key is pressed on a keyboard?
A small bar under the key pushes through a hole and makes contact with a conducting membrane.
What is the purpose of an optical mouse?
An optical mouse is used for pointing and selecting areas on a display.
How does an optical mouse detect movement?
It shines light from a red LED onto a surface and a sensor takes repeated images to compare changes.
What occurs when sound reaches a microphone?
The diaphragm vibrates, causing a coil to vibrate, which changes the magnetic field and produces a signal.
What is needed for analogue to digital conversion?
An analogue to digital converter (ADC) carries out the conversion.
Why are microphones required in mobile phones?
For telephone calls, video calls, video recording, audio recording, and virtual assistants.
What is the role of microphones in a recording studio?
One microphone is used to record each track, which are mixed together for the final music recording.
What is the function of a voice assistant microphone?
Microphones listen for a key phrase to detect further instructions.
What are the types of touchscreen technologies?
- Resistive
- Capacitive
- Infra-red
How do resistive touchscreens work?
They consist of two conductive layers separated by an insulating membrane that make contact when pressed.
What materials are used in capacitive touchscreens?
They are made up of glass layers coated with transparent conductive material, forming a grid.
How does a capacitive touchscreen detect touch?
A change in the electric field at the touch position is calculated by a microprocessor.
What are the advantages of capacitive touchscreens?
- Smooth surface
- Very easy to press
- Highly accurate
What is a disadvantage of capacitive touchscreens?
They don’t work if the user is wearing gloves.
How do infra-red touchscreens detect touch?
Infra-red LEDs shine light across the screen, and the beam interruption is calculated by a microprocessor.
What input device is required to write an essay?
Keyboard
What input device is needed to select an icon on the desktop?
Mouse
What input device is required to record a meeting?
Microphone
Choose a suitable touchscreen technology for an interactive whiteboard.
Resistive or infra-red
Choose a suitable touchscreen technology for a tablet computer.
Capacitive
