**Are you an EPFL student looking for a semester project?**

Work with us on data science and visualisation projects, and deploy your project as an app on top of GraphSearch.

Concept# Input impedance

Summary

The input impedance of an electrical network is the measure of the opposition to current (impedance), both static (resistance) and dynamic (reactance), into a load network that is external to the electrical source network. The input admittance (the reciprocal of impedance) is a measure of the load network's propensity to draw current. The source network is the portion of the network that transmits power, and the load network is the portion of the network that consumes power.
If the load network were replaced by a device with an output impedance equal to the input impedance of the load network (equivalent circuit), the characteristics of the source-load network would be the same from the perspective of the connection point. So, the voltage across and the current through the input terminals would be identical to the chosen load network.
Therefore, the input impedance of the load and the output impedance of the source determine how the source current and voltage change.
The Thévenin's equivalent circuit of the electrical network uses the concept of input impedance to determine the impedance of the equivalent circuit.
If one were to create a circuit with equivalent properties across the input terminals by placing the input impedance across the load of the circuit and the output impedance in series with the signal source, Ohm's law could be used to calculate the transfer function.
The values of the input and output impedance are often used to evaluate the electrical efficiency of networks by breaking them up into multiple stages and evaluating the efficiency of the interaction between each stage independently. To minimize electrical losses, the output impedance of the signal should be insignificant in comparison to the input impedance of the network being connected, as the gain is equivalent to the ratio of the input impedance to the total impedance (input impedance + output impedance). In this case,
(or )
The input impedance of the driven stage (load) is much larger than the output impedance of the drive stage (source).

Official source

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related publications

Loading

Related people

Loading

Related units

Loading

Related concepts

Loading

Related courses

Loading

Related lectures

Loading

Related MOOCs

Loading

Related publications (5)

Related people (1)

Loading

Loading

Loading

Related concepts (21)

Related units

Related lectures (370)

Related MOOCs (4)

Related courses (40)

AC Circuits: Understanding Impedances and Kirchhoff's Laws

Explores the application of impedance in AC circuits and Kirchhoff's laws.

Standing Wave Ratio Report

Explores standing wave ratio, load impedance, reflection coefficient, and wave propagation analysis.

Imperfections of Operational Amplifiers: Common Mode Rejection Rate

Explores the imperfections of operational amplifiers, emphasizing the common mode rejection rate and other key parameters.

Current source

A current source is an electronic circuit that delivers or absorbs an electric current which is independent of the voltage across it. A current source is the dual of a voltage source. The term current sink is sometimes used for sources fed from a negative voltage supply. Figure 1 shows the schematic symbol for an ideal current source driving a resistive load. There are two types. An independent current source (or sink) delivers a constant current. A dependent current source delivers a current which is proportional to some other voltage or current in the circuit.

Input impedance

The input impedance of an electrical network is the measure of the opposition to current (impedance), both static (resistance) and dynamic (reactance), into a load network that is external to the electrical source network. The input admittance (the reciprocal of impedance) is a measure of the load network's propensity to draw current. The source network is the portion of the network that transmits power, and the load network is the portion of the network that consumes power.

Damping factor

In an audio system, the damping factor gives the ratio of the rated impedance of the loudspeaker (usually assumed to be 8Ω) to the source impedance of the power amplifier. Only the magnitude of the loudspeaker impedance is used, and the power amplifier output impedance is assumed to be totally resistive. In typical solid state and tube amplifiers, the damping factor varies as a function of frequency. In solid state amplifiers, the damping factor usually has a maximum value at low frequencies, and it reduces progressively at higher frequencies.

, ,

This paper provides a sensorless method to control the position of keys passing through a linear actuator used in an industrial textile machine. The presented method describes how to find out the posi

2017Electrical Engineering I

Découvrez les circuits électriques linéaires. Apprenez à les maîtriser et à les résoudre, dans un premier temps en régime continu puis en régime alternatif.

Electrical Engineering I

Découvrez les circuits électriques linéaires. Apprenez à les maîtriser et à les résoudre, dans un premier temps en régime continu puis en régime alternatif.

Electronics

Introduction à l’électronique analogique- seconde partie. Fonctions linéaires de base réalisée à l’aide de transistor bipolaire.

EE-348: Electroacoustics

Ce cours a pour objectif de former les étudiants de section Génie Electrique et Electronique à la conception de systèmes acoustiques, à l'aide d'un formalisme basé sur l'électrotechnique. A la fin du

EE-320: IC design I

Introduction to the design of analog CMOS integrated circuits at the transistor level. Understanding and design of basic structures.

EE-519: Bioelectronics and biomedical microelectronics

The course covers the fundaments of bioelectronics and integrated microelectronics for biomedical and implantable systems. Issues and trade-offs at the circuit and systems levels of invasive microelec

No results

,

This paper presents a convenient and cost-effective experimental tool for measuring the mobility characteristics of a mechanical structure. The objective is to demonstrate that the point mobility meas

, ,

This paper provides a general sensorless method to control the position of a linear actuator. After a review of the solutions used so far, this new method is applied to identify keys passing through a