input devices Flashcards
1
Q
what does barcode scanner do?
A
- shines red laser at a barcode to illuminate it
- the white lines reflect the light back - the black lines absorb some light and reflect less
- the strength of the reflection from each line is interpreted by a microprocessor and converted into a binary value.
2
Q
what is barcode scanner used for?
A
- scanning goods at a supermarket checkout
- checking library books in and out
- tracking packages out for delivery
3
Q
Why is barcode scanner required?
A
- reduces errors caused by manual input
-faster checkout queues
-more detailed tracking information - automatic stock control
4
Q
What does a digital camera do?
A
- as light enters camera, falls onto sensor made up of millions of squares (pixels).
- each pixel measures light intensity
- microprocessor converts these values into digital data representing color values.
5
Q
what is digital camera used for?
A
- integrated into almost all smartphones
- security and surveillance systems
- professional photography
6
Q
Why is digital camera required?
A
- replaces traditional film based cameras
- instant photographs
- digital photos can be easily transmitted through wifi.
7
Q
what does a keyboard scanner do?
A
