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UNIT 1:
ELECTRICITY AND ELECTRONICS
(PART 3)
TECHNOLOGIES ESO 3
ELECTRICITY AND ELECTRONICS
6. EFFECTS OF ELECTRIC CURRENT
6.1 HEAT
6.2 LIGHT
6.3 ELECTROMAGNETISM
7. ELECTRONIC COMPONENTS
7.1 RESISTORS: FIXED AND VARIABLES
7.2 CAPACITORS
7.3 DIODES
6. EFFECTS OF ELECTRIC CURRENT
6.1 HEAT
The movement of electrons in a wire causes collisions and the
increase of temperature of the wire. The heat produced by an
electric current is called JOULE EFFECT.
An example of application of this effect are RADIATORS and
TOASTERS.
6. EFFECTS OF ELECTRIC CURRENT
6.2 LIGHT
There are two ways of producing light using electricity:
1) Light bulbs:
Based on the phenomenon of INCANDESCENCE: inside light
bulbs there is a filament that produces light when heated by
an electric current.
2) Fluorescent tubes:
Inside the tube there is a metallic filament, an inert gas, a
small quantity of mercury and a phosphorous layer that
covers the inner part of the tube. RS.
6. EFFECTS OF ELECTRIC CURRENT
6.3 ELECTROMAGNETISM
When there is current flowing in an electric circuit, it creates a
magnetic field. This effect is called ELECTROMAGNETIC
INDUCTION and it is used in electric motors and relays.
7. ELECTRONIC COMPONENTS
7.1 RESISTORS
There are two types of resistors: fixed and variable:
a) FIXED RESISTORS
The resistor value is color-coded with stripes.
7. ELECTRONIC COMPONENTS
b) VARIABLE RESISTORS
- POTENTIOMETERS: These are resistors whose
value can be adjusted, with a minimum value of
0 up to the maximum specified by the
manufacturer.
- RESISTORS THAT DEPEND UPON A PHYSICAL PARAMETER:
LDR (LIGHT DEPENDENT RESISTOR): The resistance
decreases as the luminous intensity increases.
THERMISTORS (TEMPERATURE DEPENDANT
RESISTOR): resistance decreases or increases
as the temperature changes.
7. ELECTRONIC COMPONENTS
7.2 CAPACITORS
A capacitor is a component that can store
an electrical charge.
7.3 DIODES
A diode is a component that allows current to
flow in only one direction. When the anode is
connected to higher voltage than the cathode,
the diode conducts.
LED are special diodes that shine when conducting.