Physical Science Lesson 10 the Structure and Properties of Matter

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

Objective  At the end of the lesson, lesson, you should be able able to relate the properties properties and structures structures of electronic devices to their uses. In the age of technology, almost everyone owns a device that has electronic devices, such as capacitors, inductors, and resistors. Have you ever wondered what materials make up the electronic devices?

Last Updated: 08.12.16

Learn about it! Electronic devices are devices are components for controlling the flow of electrons or electricity. Common examples include capacitors, inductors, and resistors. They are often small and combined into packages called integrated circuits. circuits. Capacitors  A capacitor stores capacitor stores electrical energy temporarily in an electric field. It has two electrical plates separated by a dielectric. The dielectric is dielectric is an insulator that stores energy when polarized. The electrical plates are plates are made of conductive materials, materials, such as metals and electrolytes. electrolytes. On the other hand, the nonconducting dielectrics are often made of ceramic, plastic film, and glass.

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 capacitors. Metals have free flowing electrons, so they are good conductors of electricity.

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

Learn about it! 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

 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.

Learn about it! 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.

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?

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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!

4electronic devices Electronic devices are materials that control the flow of electrons. Common examples include capacitors and resistors. Next question

1electrical devices2electric current3electric power Question 2  Which of the following materials resists changes in electric current passing through it? Incorrect!

3resistor  An inductor resists changes in electric current passing through it. It is often comprised of conductors  wound into a magnetic core. Next question

1inductor2capacitor4transistor Question 3  Which of the following stores electrical energy temporarily in an electric field? Correct!

3capacitor  A capacitor is an electronic device which controls electricity by storing it temporarily in an electric field. Next question

1inductor2resistor4transistor Question 4  Which of the following are true about the electrical plates in a capacitor?

Correct!

2They are separated by a dielectric. 4They 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

1They are made of electrical insulators.3They are attached with screws. Question 5  What are the functions of a resistor? Correct!

3reduce the amount of current4lower 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

1increase the flow of electrons2resist the change in electric current Question 6  Which of the following can be used as a dielectric? Incorrect!

2electrolyte The dielectric is an insulator that stores energy when polarized. It is made of nonconducting materials such as ceramic and glass. Next question

1glass3metal4ceramic Question 7  Which of the following are true about ferrites? Incorrect!

3They 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. Next question

2They are ceramic materials comprised of iron oxides combined with nickel, zinc, or manganese compounds.1They have high magnetic permeability and high electrical resistivity.4They 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!

2The 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

1The overall resistance of Resistor X is higher than that of Resistor Y. 3The overall resistance of Resistor X is lower than that of Resistor Y. 4The 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!

1polystyrene 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

2aluminum3ferrite4copper Question 10  Substance X is wound into a magnetic core. When electricity passes through it, reactive magnetic  fluxes are generated.

 What type of material is Substance X possibly made of?

Incorrect!

1polystyrene  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. Finish quiz

2ferrite3copper4iron