Electronics

Question 1

________ are materials that are neither good conductors nor good insulators

Answer 1

Semi-conductors

Question 2

How many valence electrons are in the outer orbit of a semi-conductor material?

Answer 2

4

Question 3

________ and ________ are the most common semiconductor materials

Answer 3

Germanium and silicon

Question 4

When semiconductor materials are refined into a pure form, the molecules arrange themselves into a structure with a definite pattern, know as a ________

Answer 4

Crystal lattice structure

Question 5

P-type materials have a net ________ charge

Answer 5

Positive

Question 6

N-type materials have a net ________ charge

Answer 6

Negative

Question 7

Solid-state devices are made by combining ________ and ________ materials

Answer 7

P-type and N-type

Question 8

If a diode is to conduct current, it must be ________

Answer 8

Forward biased

Question 9

The PN junction is often called a ________

Answer 9

Diode

Question 10

A diode is forward biased when a positive voltage is connected to the ________ and a negative voltage is connected to the ________

Answer 10

Anode, cathode

Question 11

True or false: a forward biased diode has the positive voltage connected to the cathode, and the negative voltage connected to the anode

Answer 11

False. This describes a reverse biased diode

Question 12

A ________ is a device that changes, or converts AC voltage into DC voltage

Answer 12

Rectifier

Question 13

________ is the process of introducing impurities into pure semi-conductor materials, thereby making them better conductors

Answer 13

Doping

Question 14

An N-type semiconductor is formed when an impurity having ________ valence electrons is introduced into the pure semiconductor crystal

Answer 14

5

Question 15

A P-type semiconductor is formed when an impurity having ________ valence electrons is introduced into the pure semiconductor crystal

Answer 15

3

Question 16

When working with solid-state devices, it is important to remember that circuits are often drawn using the ________ which assumes current flows from positive to negative

Answer 16

Conventional flow theory

Question 17

While a diode is made by joining a piece of P-type material with a piece of N-type material, a transistor is made by joining ________

Answer 17

3 layers of semiconductor material (PNP or NPN)

Question 18

True or false: semiconductors have a positive temperature coefficient

Answer 18

False. Semiconductors have a negative temperature coefficient. As temperature increases, resistance decreases

Question 19

To improve the dissipation of heat due to internal R losses in
semiconductor devices, devices are commonly mounted onto ________

Answer 19

Aluminum heat sinks

Question 20

Silicon diodes experience a ________ internal voltage drop, while germanium diodes typically experience a ________ voltage drop

Answer 20

0.7V, 0.3V

Question 21

True or false: the supply voltage must be greater than the voltage of the zener diode or the circuit cannot operate

Answer 21

True

Question 22

There are 4 key points when connecting a Zener diode as a voltage regulator. Name these 4 points

Answer 22

1. Ensure that the source voltage exceeds the voltage rating of the Zener
2. Connect the Zener in reverse bias
3. Use a series connected current limiting resistor to drop off the voltage difference between the Zener and the source
4. Connect the load in parallel to the Zener

Question 23

When used in a circuit, the LED generally operates with a current of about ________ or less

Answer 23

20 mA (0.02 amperes)

Question 24

Photodiodes can be used in two basic ways, either as ________ devices or as ________ devices

Answer 24

Photovoltaic, photoconductive

Question 25

The basic light-emitting diode is formed by joining ________ with ________

Answer 25

Gallium arsenide (GaAs), gallium phosphide (GaP)

Question 26

The NPN transistor must have a ________ voltage connected to the collector and a ________ voltage connected to the emitter

Answer 26

Positive, negative

Question 27

The PNP transistor must have a positive voltage connected to ________ and a negative voltage connected to the ________

Answer 27

Emitter, collector

Question 28

In order for a transistor to be forward biased, the base must be connected to the same polarity as the ________

Answer 28

Collector