Solid State Review

Question 1

The reason that copper and silver are good conductor of electricity is because they have each X valence electron

Answer 1

One

Question 2

Two type of semiconductors elements that are used are X and X

Answer 2

Silicon, Germanium

Question 3

Adjacent semiconductor atoms tend to share their valence electrons to create a stable eight electron arrangement. This arrangement is known as X bonding

Answer 3

Covalence

Question 4

N-type semiconductor materials are doped with x-valent elements

Answer 4

Penta-valent

Question 5

An example of a trivalent donor is?

Answer 5

Boron, aluminium, Gallium

Question 6

Semiconductors have a negative temperature coefficient of resistance. This means as the temperature decreases, the conductivity will?

Answer 6

Decrease

Question 7

What determines whether a material is classified as a conductor, and insulator or a semiconductor?

Answer 7

Its valence electrons

Question 8

N-Type semiconductors have an excess of X as charge carriers

Answer 8

Electrons

Question 9

P-Type semiconductors have an excess of X as charge carrier.

Answer 9

Holes

Question 10

Why is silicon more commonly used than germanium for semiconductor devices?

Answer 10

Silicon can withstand higher temperatures

Question 11

A diode is reversed biased when the anode is made X with respect to the cathode

Answer 11

Negative

Question 12

The barrier potential formed at the junction of P and N- Type materials is X for silicon diodes and X for germanium diodes.

Answer 12

0,7 Volts
0,3 Volts

Question 13

A diode breaks down and the current avalanches when the X rating of the diode is exceeded.

Answer 13

PIV - Peak-Inverse-Voltage

Question 14

To protect the switch contacts of a circuit (CCT) supplying DC current to an inductive load, X biaised diode is used. A diode applied in this fashion is called a X

Answer 14

Reverse

Freewheeling or arc-clamping or arc-suppressing.

Question 15

To protect the switch contacts of a circuit supplying DC current to an inductive load, a X biased diode is used. A diode applied in this fashion is called a X diode.

Answer 15

Reverse. * Diodes nominally conduct electricity in one direction, and the voltage they apply follows a so-called “forward bias” orientation. If the voltage moves in the opposite direction, we call that orientation a “reverse bias.” In reverse bias, current flow is nominally blocked as a sort of electronic check valve.*

Free-wheeling, arc-clamping or arc-suppressing.
* Freewheeling diode or flyback diode is a diode that is connected across an inductor to eliminate the flyback. Flyback is the sudden voltage spike that occurs across an inductive load due to interruption of supply current or sudden reduction. This voltage spike will damage the switches present in the circuits.*

Question 16

The PIV rating of an LED light is approximately X volts

Answer 16

6.0 V

** Peak Inverse Voltage (PIV) or Peak Reverse Voltage (PRV) refer to the maximum voltage a diode or other device can withstand in the reverse-biased direction before breakdown. Also may be called Reverse Breakdown Voltage. **

Question 17

The forward current rating of an LED is in the range of X to X mA

Answer 17

10 to 50 mA

Question 18

LED’s have a forward voltage drop that is X than conventional diodes.

Answer 18

Higher

* The forward voltage is dependent on what they are made of and how they are made. A normal silicon diode is made of silicon (duuu). The LED is made of a variety of materials, depending on the color of light it produces. Hence, different forward voltage.*

Question 19

Photodiodes are usually places in circuits so that they operate in X bias.

Answer 19

Reverse

* A photodiode is used to detect optical signals. The fractional change in the minority carrier dominated reverse bias current due to the photoeffect is more easily measurable than fractional change in forward bias current. Hence a photodiode is preferably operated in reverse bias condition.*

Question 20

As luminance increases, the conductivity of a photo diode will X

Answer 20

Increase

Question 21

Which colours LED (red, amber or green) has the highest voltage drop across it when conducting?

Answer 21

Green. Voltage drop of 2.1Volt

Question 22

Explain what is meant the term clamping diode.

Answer 22

A diode that is reversed bias in a AC inductive circuit. When the switch is closed and acts as an arc-suppressor (conduct) when the switch opens.

Question 23

What is a varistor?

Answer 23

A special device for voltage (arc) suppression in an AC circuit; a clipper circuit.