WHAT IS A SYSTEM
a collection of parts e.g components, or processes that work together to make something happen.
WHAT ARE EXAMPLES OF SUB-SYSTEM IN A DIGITAL CAMERA
- power
- timber
- memory
- auto-focus
SYSTEMS ARE SPLIT INTO 3 TYPES, NAME THEM
- input
- process
- output
INPUT
something put IN to achieve an outcome
PROCESS
activity that produces an output
OUTPUT
the result
DRAW AN OPEN-LOOP SYSTEM
input–> process–> output
GIVE AN EXAMPLE OF A OPEN-LOOP SYSTEM
AUTOMATIC DOORS
motion sensor–> motor drives gears to open doors–> doors open
DRAW AN CLOSED-LOOP SYSTEM
input–> process–> output–> feedback (question)——>
GIVE AN EXAMPLE OF A CLOSED-LOOP SYSTEM
KETTLE
kettleis swiched on-> element heats water-> kettle boils –> is water boiled at 100*c? yes–> pour water –> no- back to process
EXAMPLES OF INPUT COMPONENTS
- toggle switch-stays in position- on/off
- PTM- turned on when pressed
- PTB- e.g fridge light
- LDR-night light-sensitive pannel
- thermistor-resistance changes in temp-heating system
- pressure switch-pressure pad- burglar alarm
EXAMPLE OF OUTPUT COMPONENTS
- LED-low voltage/power-tv screen
- Lamp-brighter than LEDs- street lamps
- Buzzer-sounds-high pitched buzz-door entry
- Speaker-variety of sounds-headphones
WHY DO WE USE SYMBOLS FOR COMPONENTS
its simple and they aren’t hard to identify
WHAT TYPE OF SWICH WOULD BE USED IN A DOORBELL
PTM switch
WHAT IS POLARITY
the components have a positive and a negative side and can only go one way round in a circuit.
WHY WOULD YOU WANT TO CONNECT AN OUTPUT A TRANSDUCER DRIVER
to increase their power
MICRO- USB LAMP
toggle switch–> LED–> resistor
WHAT IS A PCB
printed circuit board
