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















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



38. Circuits

39. Sens du courant

40. Associations de dipôles

41. Conducteurs et isolants

42. Courts-circuits





PCCL © 2017















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.





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.





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.





- 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.
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).




- 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:



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:



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.




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.