Systems approach to designing

Question 1

What are input devices?

Answer 1

• An electronic component that can pass information from the outside world into an electronic system for processing

Question 2

What are PTM and PTB switches?

Answer 2

• Push To Make switches allow current to flow when pressed
• Push To Break switches allow current to flow when not pressed

Question 3

Types of switches and uses

Answer 3

• PTM / PTB: console controller
• Reed (magnetic) switch: window sensor on alarms
• Toggle switch: power switch
• Rocker switch: light switch
• Tilt switch: to detect if something is no longer level

Question 4

How do LDRs and thermistors work?

Answer 4

• LDR: resistance decreases when light intensity increases
• Thermistor: resistance decreases when temperature increases

Question 5

What is a microcontroller and why is it used?

Answer 5

• A computer chip used instead of a CPU that contains a processor, memory and IO devices
• Provides functionallity and intelligence to products and systems

Question 6

Purpose of process devices

Answer 6

• Take the signal from the input stage and change it in some way
• Usually involves programmable components, such as microcontrollers

Question 7

Pros and cons of microcontrollers

Answer 7

• Pros: size of circuit can be significantly reduced, can be reprogrammed many times, pins to connect several I/O devices
• Cons: cost more than traditional intergrated systems, programming software and hardware is required, language must be learned

Question 8

Purpose of output devices

Answer 8

• A device used to output device or information from a computer

Question 9

Different types of output devices

Answer 9

• Light output e.g: bulbs, lamps
• Sound output e.g: buzzers, speakers