PCB

Question 1

What is a PCB?

Answer 1

Printed Circuit Board
A permanent way of making a circuit

Question 2

What are the simple stages of making a PCB?

Answer 2

Designed on CAD
Built onto a breadboard to prototype
Production of pCB

Question 3

What are the different PCB’s?

Answer 3

Single sided - for simple circuits
Double sided - for complex circuits
Multilayer - for complex circuits
Rigid
Flex
Rigid-flex

Question 4

What do PCB materials depend on?

Answer 4

Application
Cost
Performance requirements

Question 5

What is the most common material for PCB’s?

Answer 5

FR-4 (Fire Retardant 4)

Question 6

What is FR-4 made of?

Answer 6

Composite material made of woven fibreglass cloth impregnated with an epoxy resin binder

Question 7

What are the pros of FR-4?

Answer 7

Mechanical strength
Good electrical insulation properties
Dimensional stability

Question 8

What are the cons of FR-4?

Answer 8

Poor thermal conductivity
Completely rigid
Moisture absorption

Question 9

What is a flexile material used for PCB’s?

Answer 9

PI - polyimide

Question 10

Why is PI used for flexible circuits?

Answer 10

Highly flexible
Can be bent or twisted without damaging the circuit

Question 11

Applications for flexible circuits:

Answer 11

Wearable devices
Automotive electronics

Question 12

What does the technology of the PCB refer to?

Answer 12

Types of components that are used and how they are attached

Question 13

What are some examples of technology of the PCB?

Answer 13

Through Hole Technology
Surface Mount Technology

Question 14

How does through hole technology work?

Answer 14

Uses leads which are inserted through holes that are drilled in the PCB
Soldered pads on the opposite side are either manually assembled or by automated insertion machines

Question 15

What are the two types of through-components?

Answer 15

Axial - leads extrude from either end of the component
Radial - leads extrude from the bottom of the component

Question 16

How does surface mount technology work?

Answer 16

Electrical components are mounted directly onto the surface of the PCB
Replaced through hole technology because it allows increased manufacturing automation

Question 17

How is surface mount technology applied to the PCB?

Answer 17

Usually smaller components with no leads or small leads
Solder paste is applied to the footprint of the PCB which holds the components until soldered using the reflow oven