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DIODES AND TRANSISTORS

 

 

 

Both the transistor and the diode are solid state devices where the transistor replaced the vacuum tube. The name solid is due to the fact that the transistor is solid as opposed to the hollow glass vacuum tube. Both the diode and the transistor can be used as electronic switches. They are also used in a wide variety of applications, some of which are the power supply circuits, amplifier circuits, power and communication applications. Subjects covered in the diode and transistor training are:

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DIODES:

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  • This chapter starts by introducing the PN-junction diode. The ideal diode characteristics are then studied and compared to the practical diode. The practical diode model and the complete diode model are then explained. Zener diodes and light emitting diodes (LED) along with diode testing are discussed. The topics explained in this chapter are:

    • ​PN-Junction.The Ideal Diode.

    • The practical Diode Model.

    • The Complete Diode Model.

    • Zener Diodes.

    • Light Emitting Diodes.

    • Varactor Diodes.

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COMMON DIODE APPLICATIONS:

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  • Since diodes are practically used as switches, they are useful in the design of power supply circuits as well as other applications such as voltage clipping, clamping and multiplications. The topics explained in this chapter are:

    • ​Half Wave Rectifiers.

    • Full Wave Center Tap Rectifiers.

    • Full Wave Bridge Rectifiers Filters.

    • Diode Clipper Circuits.

    • Diode Clamper Circuits.

    • Zener Voltage Regulators.

    • Power Supplies.

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​BIPOLAR JUNCTION TRANSISTOR:

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  • The bipolar junction transistor "BJT" is a three-terminal component. The three terminals are called the emitter, base and collector. The emitter and collector terminals made up of the same type of semiconductor material, either p-type or n-type, while the base terminal is made up of the other material. Transistors were designed to replace the vacuum tube. There are two types of BJT transistors, the NPN and the PNP type transistors. The topics explained in this chapter are:

    • BJT operation.

    • Transistor Construction and Operation.

    • Transistor Currents, Voltages and Ratings.

    • Transistor Characteristic Curves.

    • Transistor Specification Sheet.

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TRANSISTOR DC BIASING SCHEMES:

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  • In order for BJTs to function properly, they have to be properly biased. Various biasing schemes have been devised to suit all types of applications and economics. Biasing schemes have been designed to make the transistor circuit (current gain parameter) and temperature independent. The topics explained in this chapter are:

    • DC Biasing.

    • The Load Line.

    • Base Biasing Scheme.

    • Emitter Feedback Biasing Scheme.

    • Voltage Divider Biasing Scheme.

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AMPLIFIER CONCEPTS:

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  • Amplifiers are circuits that amplify a small signal input voltage into a larger output voltage. This is done by transforming DC power from the power supply to the output terminal of the amplifier. In this chapter, the basic amplifier concepts are discussed. The topics covered in this chapter are:

    • The ideal Amplifier.

    • Hybrid Parameters.

    • Amplifier Classifications.

    • Gain And Decibels.

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AMPLIFIER CONFIGURATIONS:

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  • BJT transistor amplifier circuits are designed with many purposes. Some are designed to provide both moderate current and voltage gains. Some are designed to provide moderate voltage gain and high current gain while others are designed for moderate current gain but high voltage gain. Some provide a 180 phase shift between the input and the output, while other simply act as buffer circuits between two circuit stages. The topics explained in this chapter are:

    • Amplifier DC components.

    • Amplifier AC components.

    • Common Emitter Amplifiers.

    • Common Base Amplifiers.

    • Common Collector Amplifier.

    • RC coupling.

    • Direct Coupling.

    • Transformer Coupling.

    • Loading Effect.

    • Multistage Amplifiers.

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