Lecture

Introduction to Small Signal Configurations

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Description

This lecture introduces the concept of small signal configurations in electronics, focusing on the modeling of transistors and their polarizations. It covers the use of models in quadrupoles, input and output resistors, voltage gain, current gain, and trans-resistance/trans-conductance. The instructor explains the methodology for studying configurations, determining key parameters like rin, rout, and gmo, and simplifying calculations using approximations. Emphasis is placed on choosing the appropriate assembly for electronic applications.

In MOOC

Electronics II

This course is an introduction to the realization of linear functions using transistors. Students apply circuit theory and learn to manipulate the small and large signal models of the bipolar transistor to realize amplification and filtering functions. The explanations are illustrated by exercises with demonstrations of simulated circuits using a Spice-type simulator that can be reproduced by the students.

Official source

Related concepts (32)

Transistor

A transistor is a semiconductor device used to amplify or switch electrical signals and power. It is one of the basic building blocks of modern electronics. It is composed of semiconductor material, usually with at least three terminals for connection to an electronic circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal.

Bipolar junction transistor

A bipolar junction transistor (BJT) is a type of transistor that uses both electrons and electron holes as charge carriers. In contrast, a unipolar transistor, such as a field-effect transistor (FET), uses only one kind of charge carrier. A bipolar transistor allows a small current injected at one of its terminals to control a much larger current flowing between the terminals, making the device capable of amplification or switching. BJTs use two p–n junctions between two semiconductor types, n-type and p-type, which are regions in a single crystal of material.

Field-effect transistor

The field-effect transistor (FET) is a type of transistor that uses an electric field to control the flow of current in a semiconductor. FETs (JFETs or MOSFETs) are devices with three terminals: source, gate, and drain. FETs control the flow of current by the application of a voltage to the gate, which in turn alters the conductivity between the drain and source. FETs are also known as unipolar transistors since they involve single-carrier-type operation.

Polarization (physics)

Polarization (also polarisation) is a property of transverse waves which specifies the geometrical orientation of the oscillations. In a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of the wave. A simple example of a polarized transverse wave is vibrations traveling along a taut string (see image); for example, in a musical instrument like a guitar string. Depending on how the string is plucked, the vibrations can be in a vertical direction, horizontal direction, or at any angle perpendicular to the string.

History of the transistor

A transistor is a semiconductor device with at least three terminals for connection to an electric circuit. In the common case, the third terminal controls the flow of current between the other two terminals. This can be used for amplification, as in the case of a radio receiver, or for rapid switching, as in the case of digital circuits. The transistor replaced the vacuum-tube triode, also called a (thermionic) valve, which was much larger in size and used significantly more power to operate.

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