1. ELECTRIC UNITS
Séquence S01 T01: Distinguer les grandeurs électriques telle que courant, tension, puissance, alternatif, continu, fréquence.
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2. The electric principles
What are the different electric source you kwnow ?
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3. The electric principles
There is two sources :
Direct current
Alternative current
Dynamo
Alternateur + -
ACCU FLASH
12 V
Noter les exemples donnés par les stagiaires
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4. Direct current sources are polarized with positive and negative poles
Direct current could be produced by an electrochemical generator like a battery or by a swinging device like a dtnamo or by cells.
Dynamo + -
ACCU FLASH
12 V
Direct current sources are polarized with positive and negative poles
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5. Uses of direct current
The direct current is used to supply electric devices like portable electric drills or electric vehicles…
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6. Direct current representation
The direction of electrons is always the same
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7. Alternative current sources
We can also use mechanical energy produced by thermical engine, that what we calle a generator.
Mais, on peut utiliser la force du vent ( les éoliennes )
En général, on utilise la force de l’eau ( centrale hydraulique ) ou de la vapeur ( centrale thermique ou nucléaire ) pour faire tourner une turbine
Un Alternateur produit l’électricité
il transforme une énergie mécanique en énergie électrique
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8. Alternative current sources
The alternative current is generally used for houses and company electrical installations.
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9. Alternative current representation
The frequency of alternative current match with the number of period per seconds.
The frequency is express in Hertz.
Le Courant Alternatif change de sens périodiquement
Une Période se divise en deux Alternances
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10. Parallel of water : the Voltage
The Voltage is an electric potential difference
Is similar to a level difference
The Voltage (U) is express in VOLT (V)
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11. Parallel of water : the current intensity (amperage)
The Amperage is similar to a throughput
The current intensity ( I ) is express in Amp ( A )
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12. Parallel of water : electric resistance
The electric resistance is similar to pipes sections
The electric resistance ( R ) is express in OHM ( Ω )
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13. Ohm’s law Volatge ( U ), electric resistance( R ) and intensity ( I )
are linked by the Ohm’s law:
U = R x I
Exercice :
What will be the intensity value of a current passing through a 100 Ω device supplied by a 12 V source?
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14. The units
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15. What units are in this light bulb ?
Volt
watt
Appel à l’information
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16. What units are in this fuse ?
Intensity - Amp
Appel à l’information
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17. Units What units are in this speaker ? resistance - Ohms 8 Ω
Appel à l’information
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