Electronic

Forward Bias And Reverse Bias (figure 1) The figure above shows a dc source across a diode. The negative source terminal is connected to the n-type material, and the positive terminal is connected to the p-type material.  This connection Figure is called forward bias. Current flows easily in a forward-biased silicon diode. (Figure 2) Turn … Read more

The p-n junction We can produce a single crystal with a p-type semiconductor on one side and n-type on the other side as shown in the figure above. The border where the p-type and the n-type region meet is called the p-n junction. Depletion Layer and Junction Voltage At the p-n junction, electrons from the … Read more

p-type semiconductor n-type semiconductor Doping Material Trivalent:aluminium, boron, and gallium Pentavalent:antimony, and phosphorus Role of doping material Atom receiver Atom donor Majority Charge Carrier Holes Free electrons Minority Charge Carrier Free electrons Holes

n-type Semiconductor A p-type semiconductor can be produced by doped some trivalent atoms into a semiconductor. Trivalent atom is atom has only three valence electrons. Examples include aluminium, boron, and gallium. The figure above shows an aluminium atom (which is trivalent ) in the centre, surrounded by four silicon atoms. We can see that, the trivalent … Read more

n-type Semiconductor The n-type semiconductor can be produced by doped some pentavalent atoms into a semiconductor. Pentavalent atoms are atoms that have 5 electrons in the valence shell. Examples of pentavalent atoms include antimony and phosphorus. The figure above shows how the silicon crystal appears after doped with a phosphorous atom, which is pentavalent. We … Read more

Doping A Semiconductor One way to increase the conductivity of a semiconductor is by doping.  Doping is a process of adding a small number of impurities to a semiconductor. The impurities added to the semiconductor are called dopants. By adding impurity atoms to a conductor can increase its electrical conductivity.  There are two types of … Read more

Flows of Free Electrons and Holes We have learned that there are 2 types of charge carrier in a semiconductor, the free electrons and the holes. The free electrons carry negative charge whereas the holes carry positive charge. If a potential difference is applied to a semiconductor, the electrons and holes will start to flow. … Read more

Free Electron and Hole If a bonded electron absorbs heat energy from the surrounding, it may be promoted to higher energy level. These electrons are free to move when they are at a higher energy level. If an electron is promoted to a higher level, a vacancy is left in the valence shell, and it … Read more

Semiconductors A semiconductor is a class of crystalline solid with conductivity between a conductor and an insulator. Example of semiconductors are: Silicon Germanium Boron Tellurium Selenium The Silicon Crystal The typical example of semiconductor is silicon. Silicon has 4 valence electrons. Each of these 4 electrons are shared with another 4 silicon atoms to form … Read more

Uses of Cathode Ray Oscilloscope In a laboratory, a cathode ray oscilloscope can be used to display different types of waveform.  measure short time interval measure potential difference (as a voltmeter) Displaying Wave Forms A cathode-ray oscilloscope can be used to display different types of waveform by connecting a power supply to the Y-input.  The … Read more