Electronics

By: Sergio Arias Parra 3ºB

ELECTRONICS

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Index

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Controlling a realy.

Basic devices with electronic components.

Integrated circuits.

Electronics components.

What is electronics?

What is electronics?

Electronics,is the study of circuits and components that modify the intensity,direction and properties of electrics currents. Electronic components are formed by semiconductors. It is through electronics that circuits and components are developed and manufeactured that enable the operation of numerous elctronic devices,such as mobile phones,computers,televisions and many other devices that we use in our daily lives. Electronics allows us capture,process,store and transmit information efficiently , facilitating communication,entertainment and technological advancement in various fields.

Electronic component symbols.

Fixed resistors

Variable resitors or potentiometers

Resistors affected by phisical factores

Capacitors

Diodes.

Transistores.

Ejemples of these physical factors are temperature and light. -Resistors that are affected by temperature are called thermistors.There are two types: -PTC(positive temperature coefficient) -NTC(negative temperature) coefficient)

Resistors affected by physical factors.

The value of variable resistor can be adjusted between zero and maxium value specified by the manufacturer.

Variable resistors or potentiometers

In a circuit, a fixed resistor impedes the flow of electric current.We show its value in ohms. By a code of coloured stripes. The first two stripes give a two-digit number.The third stripe tells us hoy many zeroes to add.The fourth stripe gives the tolerance,whic is the maximum deviation from the labelled value.

Fixed resitors

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Electronic components.

Is an electronic component made of semiconductor material that allows current to flow in one direction.It has two elctrodes:an anode(A) and a cathode(K)

Diodes

A capacitor can store electrical energy. The capacitance os a capacitor , measured in coulombs,is the charge it can store for every volt applied. It´s measured in farads A capacitor with a high capacitance can store more charge and discharges more slowly

Capacitors

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Electronic components.

Are the basic building blocks of electronics. A transistor is a switch that´s activated by a small electric current. Transistor are made of semiconductor materials and have three electrodes:the base(B),the collector(C) and the emitter(E). When the base receives a current,it allows the electrons to flow from de collector to the emitter. Transistor have three operating states: -When no current moves through the base electrons can´t flow from the collector to the emitter.The transistor is in the CUTOFF STATE. -When a lot of electrons flow through the base,the route from the collector to the emitter is totally open.The transistor is in a STATE OF SATURATION. -When the flow of electrons through the base is between the cutoff and saturation states,the transistor is in an ACTIVE STATE.The flow of electrons from the collector to the emitter is proportional to the flow of electrons through the base. We can use transistors to amplifu current or activate a device automatically by regulating the current that flows through the base.

Transistors

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Electronic components.

Integrated circuits.

Many devices use the same assemblies os electronics components.Instead os constructing the same asembly multiple times,we can use integrated circuits. Integrated circuits contain a variety of miniature electronic components,such as transistors,resistors and capacitors Integrated circuits can be analogue or digital.We can use them to make amplifiers ,oscillators,radio receivers,logic gates and microprocessors.

Basic devices with elctronic components

A security alarm

In this circuit,when the cable(AB) is connected,electrons don´t flow through the base.The cable is an easier route for the electrons to follow.When the cable is broken,electrons flow through the base .When the base is saturated,current flows from the collector to the emitter.This activates the alarma bell.

A timer

IIt works like this: -At first ,the Led is turned off because no current is flowing through the base.The transistor is in the cutoff stage. -When we push the button,current flows through the base,the transistor is activated and the LED turns on.The capacitor also begins to charge. - When we release the button,the LED stays on for some time,using current from the capacitor. -When the capacitor runs out o energy,the transistor cuts off and Led turns off.

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These two circuits detect a physical parameter usiang a sensor (LDR) and activate a realy using a transistor.

Controlling a realy.

Light-activated realy

When there´s more light ,the LDR allows the current to flow.This activates the transistor and the relay.

A timer

When there´s more light ,the LDR offers a low resistance and very little current flows through the transistor base.The transistor is in the cutoff state and the realy isn´t active

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fin

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