Physical Science Lesson 10 the Structure and Properties of Matter

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The Structure and Properties of Matter The Structure and Properties of Matter

The Structure and Properties of Matter - The

The Structure and Properties of Matter - The Uses of Different Materials According to TheirUses of Different Materials According to Their Properties and Structures: Electronic Devices

Properties and Structures: Electronic Devices

Objective

At the end of the les

At the end of the lesson, you should be ason, you should be able to relate the proble to relate the properties and strperties and structures ofuctures of

electronic devices to their uses.

In the age

In the age of technology, almost everyone owns a device of technology, almost everyone owns a device that has electronic devices, suchthat has electronic devices, such

as capacitors, inductors, and resistors.

Have you ever wondered what materials make up the

Have you ever wondered what materials make up the electronic devices?electronic devices?

Last Updated: 08.12.16

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Electronic devices

Electronic devices are components for controlling the flow of electrons or electricity. are components for controlling the flow of electrons or electricity. Common examples include capacitors, inductors, and resistors. They are often small Common examples include capacitors, inductors, and resistors. They are often small and combined into packages called

and combined into packages called integrated circuitsintegrated circuits.. Capacitors

Capacitors A

A capacitorcapacitor stores electrical energy temporarily in an electric field. It has two electrical stores electrical energy temporarily in an electric field. It has two electrical plates separated by a dielectric. The

plates separated by a dielectric. The dielectricdielectric is an insulator that stores energy when is an insulator that stores energy when polarized.

polarized. The

The electrical plateselectrical plates are made of are made of conductive materialconductive materials, such as s, such as metals andmetals and electrolytes

electrolytes. On the . On the other hand, the nonconducting dielectrics are often made ofother hand, the nonconducting dielectrics are often made of ceramic, plastic film, and glass.

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Example

Film capacitors are the most common type of capacitors. Their dielectrics are made of plastic films, such as polystyrene. Polystyrene, a synthetic polymer made from the monomer styrene, has no free flowing electrons, so it has superior insulating properties.

On the other hand, metals like aluminum are used as electrical plates in film

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Long thin strips of the metal foil with the dielectric material are sandwiched together and then wound into a tight roll.

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Inductors

An inductor resists changes in electric current passing through it. It is often comprised of conductors wound into a magnetic core. When an electric current passes through its coil, it produces a magnetic field, which in turn produces electric current. In other

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words, an inductor stores energy on the basis of reactive magnetic flux.

Example

A typical inductor has copper wires, which are good electrical conductors, wound around a magnetic iron or ferrite core. Ferrites are ceramic materials comprised of iron oxides combined with nickel, zinc, or manganese compounds. They have high magnetic permeability and high electrical resistivity.

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Resistors

A resistor reduces the amount of current and lowers the voltage levels within circuits. The reduction in current or voltage results in the transformation of electrical energy into heat. A resistor is necessary in devices that need circuit adjustments, such as those that need control of volume or dimming of light.

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Example

The most common type of resistor is the carbon resistors, which are cheap general purpose resistors. They are mainly composed of a mixture of conducting graphite or carbon powder and a nonconducting ceramic powder.

The resistive value of the resistor depends on the ratio of graphite to ceramic (conductor to insulator). If the amount of carbon is higher, then the overall resistance is lower. The mixture is then placed in an insulating material with metal wires connected to each end.

What do you think?

Why do scientists and engineers need to study the properties of different materials used in electronic devices?

Key Points

 Electronic devices are components for controlling the flow of electrons or

electricity.

 A capacitor stores electrical energy temporarily in an electric field. It has two

electrical plates separated by a dielectric. The dielectric is an insulator that stores energy when polarized.

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 An inductor resists changes in electric current passing through it. It is often

comprised of conductors wound into a magnetic core.

 A resistor reduces the amount of current and lowers the voltage levels within

circuits. It is often comprised of a mixture of conductors and insulators.

Question 1

Which of the following are components for controlling the flow of electrons?

Correct!

4

electronic devices

Electronic devices are materials that control the flow of electrons. Common examples include capacitors and resistors.

Next question

1

electrical devices

2

electric current

3

electric power

Question 2

Which of the following materials resists changes in electric current passing through it?

Incorrect!

3

resistor

An inductor resists changes in electric current passing through it. It is often comprised of conductors wound into a magnetic core.

Next question

1

inductor

2

capacitor

4

transistor

Question 3

Which of the following stores electrical energy temporarily in an electric field?

Correct!

3

capacitor

A capacitor is an electronic device which controls electricity by storing it temporarily in an electric field.

Next question

1

inductor

2

resistor

4

transistor

Question 4

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Correct!

2

They are separated by a dielectric.

4

They are made of conductive materials.

A capacitor has two electrical plates separated by a dielectric. The plates are made of conductive materials, such as metals and electrolytes.

Next question

1

They are made of electrical insulators.

3

They are attached with screws.

Question 5

What are the functions of a resistor?

Correct!

3

reduce the amount of current

4

lower the voltage levels

A resistor reduces the amount of current and lowers the voltage levels within circuits. The reduction in current or voltage results in the transformation of electrical energy into heat.

Next question

1

increase the flow of electrons

2

resist the change in electric current

Question 6

Which of the following can be used as a dielectric?

Incorrect!

2

electrolyte

The dielectric is an insulator that stores energy when polarized. It is made of nonconducting materials such as ceramic and glass.

Next question

1

glass

3

metal

4

ceramic

Question 7

Which of the following are true about ferrites?

Incorrect!

3

They have no free flowing electrons, so they have superior insulating properties.

Ferrites are ceramic materials often used as the core of inductors. They are comprised of iron oxides combined with nickel, zinc, or manganese compounds. They have high magnetic permeability and high electrical resistivity.

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2

They are ceramic materials comprised of iron oxides combined with nickel, zinc, or manganese compounds.

1

They have high magnetic permeability and high electrical resistivity.

4

They are mainly composed of a mixture of conducting graphite or carbon powder and a nonconducting ceramic powder.

Question 8

Resistors X and Y are carbon resistors. The ratio of graphite to ceramic in Resistor X is greater than one. However, for Resistor Y, that ratio is less than one.

Which of the following is true about Resistors X and Y?

Incorrect!

2

The overall resistance of Resistors X and Y are equal.

The resistive value of the resistor depends on the ratio of graphite to ceramic (conductor to insulator). When there is more conductor than insulator (graphite/ceramic >1), then the overall resistance is lower.

Next question

1

The overall resistance of Resistor X is higher than that of Resistor Y.

3

The overall

resistance of Resistor X is lower than that of Resistor Y.

4

The overall resistance of Resistors X and Y cannot be compared from the given data.

Question 9

Substance A is sandwiched between two electrical plates in a film capacitor. What type of material is Substance A possibly made of?

Correct!

1

polystyrene

Film capacitors have dielectrics often made of plastic films, such as polystyrene. Polystyrene, a synthetic polymer made from the monomer styrene, has no free flowing electrons, so it has superior insulating properties.

Next question

2

aluminum

3

ferrite

4

copper

Question 10

Substance X is wound into a magnetic core. When electricity passes through it, reactive magnetic fluxes are generated.

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Incorrect!

1

polystyrene

A typical inductor has copper wires, which are good electrical conductors, wound around a magnetic iron or ferrite core. When an electric current passes through the coil, it produces a magnetic field, which in turn produces electric current.

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