Accueil Mecanique Electricité Optique Chimie Matière

 

 

Animations Flash ®  pour apprendre l' ÉLECTRICITÉ

     

 

 

 

Les bases

 

01. Associations de dipôles | série vs dérivation     en  es

 

02. Courts-circuits | activité    en  es

 

03. Courts-circuits | pourquoi c'est dangereux ?    en  es   

 

04. Schématiser des circuits simples    en  es

 

05. Conducteurs et isolants    en  es  

 

06. Analogie hydraulique | tension vs intensité    en  es

 

07. Le sens du courant | la diode    en  es 

   

 

Mesures et lois des circuits

 

08. Le multimètre - présentation    en  es 

 

09. Lois des tensions (2 lampes)    en  es

 

10. Lois des tensions (lampe + R)    en  es

 

11. Lois des intensités    en  es

 

12. Résistance - Loi d'Ohm    en  es

   

 

Tensions alternatives

 

13. Aimant/bobine | Production tension alternative    en  es

 

14. Tension variable : le tracé "à la main"    en  es

 

15. Amplitude, fréquence, période, Ueff    en  es

 

16. Oscilloscope | principe de fonctionnement    en  es

 

17. Amplitude et sensibilité verticale    en  es

 

18. Période et sensibilité horizontale    en  es

 

19. Fréquences des notes    en  es

 

20. Oscilloscope & GTBF    en  es

 

21. Puissance | coupe-circuit | surintensité    en  es

 

 

 

 

 

 

 

 

  

 

 

 

Électromagnétisme

 

22. Le spectre magnétique d'un aimant droit    en  es

 

23. Le champ magnétique créé par un courant | Solénoïde en  es

 

24. 4 activités sur le champ magnétique | Solénoïde long  en es

 

25. Force de Laplace | Rail | Règle des 3 doigts (main droite)  en es

 

26. Force de Laplace | moteur électrique | principe    en  es

 

27. Force de Laplace | le haut-parleur | principe    en  es

 

28. Moteur électrique | Transferts d'énergie | Rendement   en  es

   

 

Exercices corrigés

 

29. Circuit électrique    en  es  

 

30. Intensité  en  es

 

31. Tension  en  es

 

32. Résistance  en  es

 

33. Tension alternative          en          es

  

34. Production U alternative          en          es

 

 

   en es

 

 

 

   en es

 Livrets

 

38. Circuits

39. Sens du courant

40. Associations de dipôles

41. Conducteurs et isolants

42. Courts-circuits

 

 

 

 

PCCL © 2017

 

 

 

 

 

 

 

 

 

 

 

 

content

 

What is an electrical circuit?

 

Simple electrical circuit with a single lamp or a motor:

- Role of the generator;

- Son of connection;

- Role of the switch.

Drawing the diagram, standard symbols.

Concept of the loop.

Approach to the concept of a short circuit.

 

 

Simple electrical circuit loop

 

 generator, switch, lamp, motor, LED, diode, son of connection resistance (ohmic conductors), limiting itself, besides the switches to a generator and three components.
 

 

 

Influence of the order and number of components other than the generator.


Conductors and insulators.
Special cases of the switch and the diode.
Conducting nature of the human body.

Conventional current.

 

Series and parallel bulbs

 

The electrical circuit comprising leads.

 

Back to the short circuit: the distinction between short-circuit of a generator and short circuit of a lamp.

Security.

 

LAWS OF CURRENT

 

Current and voltage

 

Introduction procedure of intensity and tension.

Intensity : measurement, unit.

Voltage : measurement, unit.

Notion of branch and node.

Laws uniqueness of the intensity direct current in a series circuit and additivity of the intensity in a circuit with leads (parallel components)

Additivity law verified for the voltage.

The behavior of a single loop circuit is independent of the order of the components associated in series that constitute it.

Universal (independent of the object) of the two previous laws.

Adaptation of a component in a given generation.

Current and voltage.

Overvoltage and undervoltage.

 

 

Resistance

 

Experimental approach to the "resistance" electric.

Unit of electrical resistance.

 

 

Ohm's Law

 

The model of the component derived ohmic experimental results.
Ohm's law.

Safety: Fuse.

 

- Conduction and electrical structure of matter

 

The electron: understanding the electrical conduction in metals

All metals conduct electricity. All solids do not conduct electrical current. Electrical conduction in metals is interpreted by moving electrons.

 

- The ion: Understanding the electrical conduction in aqueous solutions

All aqueous solutions do not conduct electrical current.
Conduction of electrical current is interpreted by a displacement of ions.

 

- ELECTRICITY AND AC (alternative current) ELECTRICAL CIRCUITS

 

 

- From the power plant to the user

The alternator is the part common to all power plants.
The energy received by the generator is converted into electrical energy.
Distinction between renewable energy sources or not.

 

The alternator

Tension, time-varying, can be obtained by moving a magnet near a coil.

 

DC and AC voltage periodically

DC voltage and variable over time, periodic alternating voltage.
Period.
Maximum and minimum values of a voltage.

 

The oscilloscope and / or acquisition interface, the instrument measures the voltage and duration
The frequency of a periodic voltage and its unit, the hertz (Hz) in the International System (SI).
Relationship between period and frequency.
The voltage is alternative. It is sinusoidal.
The frequency of the mains voltage in France is 50 Hz

For a sinusoidal voltage, an voltmeter used AC indicates the effective value of this voltage.

This effective value is proportional to the maximum value.

 

- Electrical Power and Energy

 

Power : rated power a device.
The watt (W) is the power unit of the International System (SI).
Statement reflecting for a resistive component, the relation P = U, where U and I magnitudes are effective.
The intensity of electric current in a wire should not exceed a value determined by a safety criterion.
The circuit breaker protects equipment and installations against surges.

 

Energy : Energy: Electrical energy E transferred for a time t to a unit rated power P is given by the relation
E = P.t
The joule (J) is the energy unit of the International System (SI).

 

- ELECTRICAL AND DC

 

- Transfers of energy in a generator and a receiver.

 

Electric power We received by a receiver, through which the current I, during Δt :

We = (VA-VB) I Δt

with UAB = (VA-VB) > 0.

Electrical power transfer:

P = UABI.

 

Joule effect : applications

 

Electrical energy transferred from the electric generator to the rest of the circuit during Δt :

We = (VP-VN) I Δt

(VP-VN) = UPN means the voltage between the positive and negative terminals of the generator and I the current passing through it.
Electrical power transfer:

P = UPN I

 

Summary of energy transfer during Δt

Receiver absorbs electrical energy UAB I Δt , and "clears" some r.I2.Δt and converts the rest in another form (mechanical, chemical ...).
A generator converts partly a form of energy (mechanical, chemical ...) E.I.
Δt into electrical energy available UPN.I.Δt

Complement r.I2.Δt is dissipated as heat by Joule effect.

 

- Behavior of a global circuit

 

Distribution of electric power during Δt :

We(generator) = ΣWe(receivers)

Justification energy additivity law of tension and intensity (node or junction law = Kirchhoff's Law) .

 

Study of parameters affecting the energy transferred by the generator to the rest of a resistive cicuit:
- Influence of the electromotive force E
- Influence of resistance and their associations
- Relation : I = E / Req

- Maximum power available at the terminals of a generator, tolerated by a receiver.

 

- MAGNETISM. ELECTROMAGNETIC FORCES

 

Magnetic field

 

Action of a magnet, a current, a very short needle.
Magnetic field vector B : direction, meaning, value and unit.
Examples of magnetic field lines, uniform magnetic field.
Superposition of two magnetic fields (vector addition)

 

Magnetic field created by a current

 

Proportionality of the field value B and the current in the absence of magnetic media.
Magnetic field created by:
- A straight current;
- A solenoid.

 

Electromagnetic forces

 

Laplace's law :

management, direction, value of the force: F = I.l .B.sinα

 

Electromagnetic coupling

 

Conversion of electrical energy into mechanical energy. Role of Laplace forces. Observation of the effect associated with the reciprocal motion of a circuit in a magnetic field: conversion of mechanical energy into electrical energy.

 

- Changes in electrical systems

 

In case of a component RC

 

The capacitor

Brief description, symbol.
Charges frames.
Current: Flow of loads.
Algebraization in agreement receiver i, u, q.

Intensity-dependent relationship for a capacitor i = dq/dt, q capacitor charge in agreement receiver.
Charge-voltage relationship q= C.u ; capacity, unit the farad (F).

 

RC Component

Component response of a RC to a level of voltage: voltage across the capacitor, the current intensity, experimental and theoretical study (analytical solution).
Energy stored in a capacitor.
Continuity of the voltage across the capacitor.
Know the symbolic representation of a capacitor.
 

 

In case of a RL component

 

The coil

Brief description of a coil symbol.
Voltage across a coil receiver convention:
                   

u = ri + L di /dt

Inductance: the unity henry (H).

 

Component RL

Current response of a coil to a voltage step: experimental and theoretical study (analytical solution).
Energy stored in a coil.
Continuity of current in a circuit containing a coil.

Free oscillations in a series RLC circuit
Oscillatory discharge of a capacitor in a coil.
Influence of depreciation: periodic regimes, pseudo-periodic, aperiodic.
Natural period and pseudo-period.
Interpretation energy: energy transfer between the capacitor and the coil, the Joule effect.
Analytical resolution in the case of a significant depreciation.
Expression of the natural period

T0 = 2 Π LC

Maintenance of oscillations.

 

- To produce signals to communicate

 

Electromagnetic waves, medium of choice to transmit information

Transmission of information

Through various examples, show that the simultaneous transmission of several information requires a "channel" assigned to each.
Interest in the use of a wave: long-range transport of a signal containing information without transport of matter but with transmission.
 

 

The electromagnetic waves

Propagation of an electromagnetic wave in vacuum and material media in many ...
Classification of electromagnetic waves at the frequency and the wavelength in vacuum.
Role of a transmitting antenna (creation of an electromagnetic wave), a receiving antenna (obtaining an electrical signal from an electromagnetic wave).
 

 

Module of a sinusoidal voltage

Information and modulation
Mathematical expression of a sinusoidal voltage :

u(t) = Umax cos(2πft + Φ0)

Parameters can be modulated: amplitude, frequency and / or phase.

 

2. Amplitude modulation

2.1 principe de la modulation d'amplitude

Amplitude modulated voltage: voltage whose amplitude is linear function of the modulating voltage.
An embodiment of an amplitude modulation.
Concept of modulation.
Choice of signal frequency to be modulated according to the characteristic frequencies of the modulating signal.
.

 

Principle of the amplitude demodulation

Functions to be performed to demodulate an amplitude modulated voltage.
Experimental verification:
- The envelope detection performed by the group consisting of the diode and RC parallel assembly.
- The elimination of the DC ../forums/img/Marseille/forum_arrow.gif by an RC high-pass filter.
Restitution of the modulating signal.

 

Realization of a disposotif to receive a radio amplitude modulation

The component coil capacitor connected in parallel experimental study, by modeling a parallel LC circuit.
Association of the component and an antenna for receiving an amplitude modulated signal.
Production of a radio receiver in amplitude modulation.