types of systems Flashcards
system
a system comprises of parts or components that work together to control a task or activity, consists of inputs, processes and outputs
open loop system
a simple system that has no feedbacks e.g an electric heater-it will remain on until switched off by the user
closed loop system
a system able to make a decision using a form of feedback e.g a central heating system-will automatically turn itself on and off when the temperature reaches a certain value
input
needs some form of trigger to make it work e.g switch or sensor
processes
process devices make all the decisions in the system, process input information to determine the output
outputs
deliver the function the input and process work to achieve, determines how the system responds to the input
toggle switch (latching)
input
on and off positions, once switched they stay in that position
lighting, power switches, control panels
push to make (PTM) switch
input
connection is made only when the switch is pressed down
door bell, keyboard, intercom
push to break (PTB) switch
input
connection is made only when the switch is released
alarm systems, control systems
light dependent resistor (LDR)
input
light sensitive panel, resistance increases the darker it gets
solar garden lights, street lights, security lights
thermistor
input
a change in temperature connects or breaks the circuit
thermostats on central heating systems of refrigerators
pressure switch
input
on/off due to pressure being applied, can also be used to detect gradual pressure
burglar alarm systems, video game floor mates
integrated circuits
process
they combine different electrical components and are found in most electrical products e.g calculators, mobile phones
how do chips simplify electronic systems?
by reducing the number of separate components making the cheaper, easier and smaller to install
pros of chips
use less power than individual components
