Hardware Flashcards
contents Computer archiecture
CPU(central processing unit)
ALU(arithmetic logic unit)- arithmetic
CU(control unit)
RAM(random access memory)
CPU
central processing unit-
execution or processing of all the instructions and data
ALU
arithmetic logic unit-
arithmetic and logic operations
CU
control unit-
reads an instruction from memory
RAM
random access memory-
stores data for the CPU
volatile, data will be lost if computer gets shut down
faster to read and write from
CIR
current instruction register-
this register stores the current instruction being decoded and executed
ACC
accumulator-
this register is used when carrying out ALU calculations; it stores data temporarily during the calculations
MAR
memory address register-
this register stores the address of the memory location currently being read from or written to
MDR
memory data register-
this register stores data which has just been read from memory or data which is about to be written to memory
PC
program counter-
this register stores the address where the next instruction to be read can be found
Address bus
carries address throughout the system Between the CPU and memory, can only carry address in 1 direction
Data bus
data can be sent both directions, carries data to and from the CPU and memory, also input and output devices
control bus
carries signals from the control unit to all the other computer components, can also travel in both directions
fetch-decode-excute cycle
the cpu fetches data and instructions and stores them in registers both the address and date buses are used, then it decodes each instruction before finally executing it
barcode scanner
red light is shone on the barcode
the white parts reflect the light back
the reflected light is read by the scanner
it is then converted to digital data
camera
light passes through the lens onto a light-sensitive cell
the image is converted into tiny electric charges, passed through the ADC
converts electrical charges into pixels and colour
keyboard
each character has its own unique ASCII value
when pressed the ASCII value is sent to the computer
the computer interprets that and displays it into the screen
microphones
when sound is created the air vibrates
the diaphragm picks up the air vibrations
the diaphragm causes the cone to move in and out causing the copper coil inside to move
the coil causes and electric current where it is converted back to sound
optical mouse
a red LED is bounced off the surface which helps navigate the computer
2-D scanner and 3-D scanner
document/object is placed inside the scanner
a light is used to help create an image
the image is then sent to the computer which then displays it onto a screen
capacitive touchscreen
composed of a protective layer, conductive layer, and a glass substrate
better image clarity
multi-touch
only works with bare fingers
infrared touch screen
there are infrared rays shinning throughout the screen
when u touch the screen u block the light allowing the processor to know the location of your finger on the screen
good screen durability
multi touch
sensitive to water
possible light interference
inkjet printer
data is sent from computer to printer
printer driver ensures printer can understand data and check is used to check the availability of printer
data stored in printer buffer and paper is inserted
the printer head moves from side to side across the document until it is complete
LED screen
made up of tiny LEDs
consumer less power
brighter
