2414

In order to better visualize the operation of a BJT as an amplifier, it is useful to represent it by an equivalent circuit. Two types of equivalent circuits representations are used based on h-parameters (Hybrid) and r-parameters. For this course we shall limit our discussion to r-parameters. There are three basic BJT connections

JFETs must be operated such that gate source junction is always reverse biased. the condition requires negative voltage for an n channel .

In order to better visualize the operation of a BJT as an amplifier, it is useful to represent it by an equivalent circuit Two types of equivalent circuits representations are used based on h-parameters (Hybrid) and r-parameters For this course we shall limit our discussion to r-parameters

Bipolar junction transistors and operational point for the load lines

BJTs are conducted with three doped semiconductor regions separated by two pn junctions the three regions are called emitter, base and collector

Third approximation can be used to account more accurately for diode forward voltage drop The diode I-V characteristic is not vertical above the knee voltage but actually slopes upwards to the right This means that as more current flows through the real diode, more voltage is dropped across it Once the diode conducts, it acts like a resistor

The key function of zener diode is its ability to maintain nearly constant voltage across its terminal over a wide range of reverse circuit. it is widely used for voltage regulation

Biasing means applying a fixed Direct electric component (current or voltage). The primary usefulness of a pn junction is its ability to allow current in only one direction There are two types of PN junction biasing Forward Bias Reverse Bias

All matters are made of atoms made of electrons, protons and neutrons An atom is the smallest particle of an element and each element has a unique atomic structure According to Bohr Model, atom structure has central nucleus and orbiting electrons Each type of atom has a certain number of electrons and protons different from atoms of other elements

electrolytic capacitors are basically conductive, salt in solvent. aluminum electrodes are used by using a thin oxidation membrane and explode if the rated voltage is exceeded or polarity is reversed