Mechatronic Systems Engineering 2201A/B Lecture Notes - Lecture 16: Electric Field, Valence And Conduction Bands, Depletion Region
13 Jan 2020
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A diode has two terminals which are called the anode and the cathode. The reference polarity of voltage across diode is positive at anode and negative at cathode. The positive reference direction of current is from anode to cathode. Diodes readily conduct current in the positive direction (from anode to cathode) but do not readily allow current to flow in the opposite (from cathode to anode) direction. Forward bias region: small positive voltage results in a relatively large positive current. Reverse bias region: moderate negative voltage results in a very small negative current. Reverse breakdown region: sufficiently large negative voltage results in a large negative current. Conductors: (such as metals) are materials that have atoms with a large number of weakly bound electrons. When an electric field is applied to a conductor, the electrons migrate freely producing a current through the material. Insulators: materials that have atoms with tightly bound electrons.
