4.1.2-4.2 transistors integrated circuits and PCB

Question 1

What are the 5 types of transistors?

Answer 1

BJT Bipolar Junction transistor
UJT unijunction transistor
Phototransistor
JFET junction field affect transistor
MOSFET metal oxide semiconductor field effect transistor

Question 2

What is a transistor used for?

Answer 2

Switching and controlling a current in a circuit

Question 3

How many junctions does a BJT have?

Answer 3

Three

Question 4

If the arrow is pointing inwards (emitter) on a BGT is this PNP or NPN?

Answer 4

PNP

Question 5

What are the two junction transistors?

Answer 5

UJT and BJT

Question 6

How many depletion areas are there on a BGT?

Answer 6

Two with three parts of P+N type semiconductor material

Question 7

How is current controlled in an FET?

Answer 7

By the action of an electron field

Question 8

What are BJT’s predominantly used for?

Answer 8

Amplification and switching

Question 9

What is an integrated circuit

Answer 9

Combination of several electronic components in common housing

Question 10

What are the three advantages of ICS?

Answer 10

Very high density of components
Very compact
Quite resistant mechanical stress

Question 11

What are the two disadvantages of ICS?

Answer 11

Small housing or requires heat sink for cooling
Cannot be repaired faulty IC must be replaced

Question 12

What three components can be integrated into an IC?

Answer 12

Semiconductor (transistor and diode)
Resistors
Capacitors

Question 13

ICS can be found in what type of appliances?

Answer 13

All modern appliances, both analog and digital

Question 14

What are the three basic logic gates?

Answer 14

NOT
AND
OR

Question 15

What is an NOT logic gate commonly known as?

Answer 15

An inverter

Question 16

Is radio frequency integrated circuit linear or non-linear?

Answer 16

Non-linear

Question 17

What is the main purpose of an operational amplifier?

Answer 17

Integrated circuit that can amplify weak electrical signals

Question 18

How many voltage supplies does an amp have?

Answer 18

2 DC voltage supplies

Question 19

What is at the input and output stages of an operational amplifier?

Answer 19

Input stage differential amplifier
Output stage push pull power amplifier

Question 20

How would you receive positive feedback?

Answer 20

Connecting output to the positive terminal input
(connecting to negative terminal gives negative feedback)

Question 21

What are the most common uses of an operational amplifier? (5)

Answer 21

Inverters
Buffers
Differential
Summing
Comparative

Question 22

What does an inverter do to the input?

Answer 22

Invert the input

Question 23

What is the main purpose of a differential op amp?

Answer 23

It is a voltage subtracter

Question 24

What is the main purpose of a printed circuit board (PCB)?

Answer 24

It is a mounting surface which physically supports electrical circuit components

Question 25

What are the two main materials used for PCB?

Answer 25

Copper laminated paper treated with epoxy resin Copper laminated glass silk weave reinforced with fibreglass

Question 26

Why is epoxy resin used with copper laminated paper?

Answer 26

For its flame resistant properties

Question 27

What two main steps are there in producing a PCB?

Answer 27

Patterning- circuit diagram into pattern using CAD Printing - pattern to PCB

Question 28

What are the two methods of printing the pattern to the PCB?

Answer 28

Etching method Addition method

Question 29

What’s printing method works by dipping the PCB into an acidic solution?

Answer 29

Etching method

Question 30

What is the main difference between single sided board and double sided board?

Answer 30

Single sided board has wiring on one side components on reverse Double sided board has wiring on both and may have components on both sides

Question 31

What is the disadvantage of multi layer board?

Answer 31

Internal plane act as a heat sink

Question 32

When would automatic or mass soldering be required?

Answer 32

For mass batch production of PCB

Question 33

What are these and advantage for? Smaller parts Denser layout Cheaper PCB Improve shock and vibration Shielding from EMI

Answer 33

SMT surface mount

Question 34

What is SMT also known as?

Answer 34

Planar mounting