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Flash Animations for ELECTRICITY learning







Basic Concepts


01. Simple circuit   


02. Parallel or series circuit | activity   


03. Short circuit | an activity   


04. Short circuit | why is it so dangerous ?   


05. Circuit diagram | to draw simple circuits   


06. Electrical conductors vs insulators   


 07. Hydraulic analogy | voltage vs current   


 08. Direction of the current | the diode   



Measuring and laws of circuits


09. Multimeter | measuring voltage, current and resistance   


10. Kirchhoff's Voltage Law (KVL) | 2 bulbs


11. Kirchhoff's Voltage Law (KVL) | 2 bulbs 


12. KVL | 2 bulbs + regulated DC power supply 


13. Kirchhoff's Voltage Law (KVL) | 1 bulb & 1 resistor   


14. Kirchhoff's Current Law (KCL) | 1 bulb & 1 resistor   


15. Kirchhoff's Current Law (KCL) | 2 bulbs      BETA


16. Ohm's Law | resistor behavior, characteristic curve   



Alternating Current - AC


17. Magnet & coil for AC production   


18. Graph of AC voltage over time   


19. Sine waveform voltage, period, peak voltage, RMS   


20. Oscilloscope | principle of working   


21. Oscilloscope | reading the peak voltage (amplitude)   


22. Oscilloscope | reading the period   


 23. Oscilloscope | displaying the form of an audio signal   


 24. Oscilloscope | sine, square & triangle signal   


 25. Electric power | fuse | overcurrent   















26. Magnetic field | Bar magnet field lines   


27. Solenoid | magnetic field, voltage & current   


28. Solenoid | 4 activities   


29. Lorentz force application : rail gun | right-hand rule   


30. Lorentz force application : electric motor   


31. Lorentz force application : speaker   


32. Motor efficiency | energy tranfers   



Practice Questions


33. Electric circuit diagrams   


34. Kirchhoff's Current Law


35. Kirchhoff's Voltage Law


36. Electric resistance | Ohm's Law for a resistor


37. AC voltage | oscilloscope | Vpeak | Vrms | frequency


38. AC voltage production







42. Simple electric circuits


43. Current direction


44. Series and parallel circuits


45. Conductors vs insulators


46. Short Circuits








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What is an electrical circuit?


Simple electrical circuit with a single lamp or a motor:

- Role of the generator;

- connection wire;

- 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, connection wire, 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.