2. Tutorial: Mechanic - electrician Topic: Technical training II. class Semiconductor devices 1 Prepared by: Melichařík Lubomír Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.

3.  SEMICONDUCTORS  A semiconductor is a solid material, whose electrical conductivity depends on external or internal conditions, and one can easily change these conditions influence. A change in the external conditions meaning the delivery of some type of energy – usually heat, electricity or light, a change in the internal conditions by introducing a dash of a different element in the semiconductor.

4.  TYPES OF SEMICONDUCTORS  Among the semiconductor elements are:  -silicon  -germanium  -selenium  -compounds gallium arsenide GaAs  -Lead sulphide PbS  Most semiconductors are crystalline substances, but there are also amorphous semiconductors (some glass)

5.  SEMICONDUCTOR DIVISION  By structure - organic, inorganic  According to the major charge carriers - n- semiconductors, p-semiconductors  According to the origin of charge carriers –proper semiconductors, step-semiconductors  According to the nature of the jump over mechanisms between the bands -direct semiconductors, indirect semiconductors According to the statistical distribution of the carriers- undegenerate semiconductor, degenerate semiconductor

6.  N-type Semiconductor  If we add to pure silicon with four valence electrons an element with five valence electrons (phosphorus, arsenic or antimony), there will be an N-type semiconductor.  P-type Semiconductor  If we endow a silicon element with three valence electrons (boron, aluminum, gallium or indium)a P-type semiconductor is created.  Using semiconductors additives  Semiconductor additives are used in semiconductor devices, primarily in the semiconductor diode and transistor, where they play a crucial role in the P-N junction.

7.  Semiconductor device  is an electronic device utilized for its functional specific properties as a semiconductor such as germanium (Ge) and silicon (Si)  Semiconductor devices are: Diodes, bipolar and unipolar transistors, thyristors, diacs and triacs.

8.  BASIC SCHEMATIC SYMBOLS  Electrotechnical schematic symbol for diodes  Electrotechnical schematic symbol for an NPN transistor  Electrotechnical schematic symbol for a PNP transistor

9.  1. What is a semiconductor?  2. Name the types of semiconductors.  3. How are semiconductors divided?  4. What is a semiconductor device?

10.  1. Draw the schematic symbol for diodes  2. Draw the schematic symbol for an NPN transistor  3. Draw the schematic symbol for a PNP transistor

11.  Václav MalinaPoznáváme elektroniku I.  Adrian Schommers Elektronika tajemství zbavená. ISBN 3-92608-32-5