投稿者: nagakura

What Is a Terminal?

A terminal is an element placed at the end of an electronic device that serves as a connection point for the input and output of power and signals. Pairs of inputs and outputs together are called a terminal pair or port. The component used to connect terminals together is called a connector.

What Is an Interface?

Interfaces are classified according to the object to be connected, and there are three main types:

• Hardware Interface
  Components that connect electronic devices (terminals, connectors, etc.)
• Software Interface
  A mechanism for exchanging data between software (e.g., operating system)
• User Interface
  Input/output parts for human handling of devices such as PCs (e.g., keyboards)

Types of Terminals

Terminals mainly refer to AV terminals for audio and video input/output that have been used for PCs and game consoles. Today, HDMI and USB terminals are the most common.

1. RF Terminal

RF terminals were used for input/output of radio wave equipment, input/output of high-frequency measurement equipment as well as input/output of LCD TVs, etc. and antenna input of tuners, etc.

2. RCA Terminals

RCA terminals have three colors (red, white, and yellow). The red and white terminals provide stereo audio input and output, and the yellow terminal provides video input and output.

3. Component Terminals

Component terminals are high-performance terminals that input and output video signal from and to RCA using three terminals.

4. BNC Terminal

This terminal is used for professional AV equipment because it is easy to connect and disconnect and has high performance.

5. VGA Terminal

The VGA terminal is used for input/output when connecting a PC to a display, projector, or other device to project images.

6. DVI Terminal

The DVI terminal is used for digital video output.

7. HDMI Terminal

The HDMI terminal is a derivative of DVI and allows video and audio to be transmitted over a single cable.

8. USB Terminal

USB terminals were primarily used to connect PCs and peripherals, but now they can also supply power and provide the same quality of video and audio input/output as HDMI.

What Are Metallic Materials?

Metallic materials are materials made by materials that have metallic properties.

They are used in a wide variety of applications due to their strength, ductility, melting properties, electrical conductivity, thermal conductivity, and other advantages.

When selecting metallic materials, it is necessary to select the most suitable material in terms of strength, heat resistance, corrosion resistance, workability, cost, etc., according to the environment in which the product will be used and the available processing methods.

The types of metallic materials can be broadly classified into iron and steel materials, which are mainly composed of iron, and nonferrous metallic materials, which are mainly composed of metals other than iron.

Steel Materials

Steel materials are inexpensive materials with excellent strength and ductility. They are used in a variety of applications because their mechanical properties can be adjusted through heat treatment and the addition of other metals.

Iron and steel is an iron alloy containing about 0.04%~2% carbon, but it is often referred to as a generic term for materials in which iron is the main component.

Stainless steel is a material to which 12% or more chromium is added to steel.

Nonferrous Metallic Materials

Nonferrous metallic materials are a generic term for materials composed mainly of metals other than iron, such as aluminum, titanium, magnesium, nickel, and copper.

Although they are more expensive than steel materials, they are used in situations where functional properties such as light weight and wear resistance are required.

1. Aluminum

Aluminum is light, weighing only 1/3 of steel, and is used as a highly functional material with excellent corrosion resistance and elongation properties. Although it may seem low in strength, when copper or magnesium is added, it becomes a high-strength material known as duralumin.

2. Copper

Copper has excellent thermal conductivity, electrical conductivity, workability, and ductility, and is used as a component material for electrical products. There are various types of copper materials such as bronze (an alloy of copper and tin), brass (an alloy of copper and zinc), and chrome copper.

What Is Semiconductor Manufacturing?

Semiconductor manufacturing is the production of single-crystal rods (silicon ingots) and wafers sliced from polycrystalline silicon and other materials, which are semiconductors.

A semiconductor is a material with properties between those of a conductor and an insulator. Integrated circuits made from semiconductors have excellent information processing capabilities and are indispensable products for all industries.

The front-end process consists of wafer fabrication, oxide film formation, pattern formation, device formation by ion implantation, diffusion, etc., repeated surface planarization, electrode formation, and wafer inspection.

The latter half of the process consists of cutting the wafer into chips, protecting the chips from the external environment, packaging the chips for signal input/output to/from peripheral components, or mounting the chips on substrates, and inspection.

What Is an Amplifier?

An amplifier is a device that amplifies electrical signals, especially in the field of acoustics.

Types of Amplifiers

1. Preamplifier

Preamplifiers switch the input signals of various sound sources such as FM broadcasts and CDs, and adjust the sound quality.

2. Power Amplifier

The power amplifier amplifies the electrical signals sent from the preamplifier and sends them to the speakers. It is also called a main amplifier.

3. Pre-Main Amplifier

This type of amplifier combines the functions of both a preamplifier and a power amplifier, and is very useful for audio purposes.

How to Select an Amplifier

When selecting an amplifier, it is important to keep the following points in mind:

1. Availability of a USB Port

A USB port is necessary to connect a smartphone, digital audio player, or PC to an amplifier.

2. High-Resolution Compatibility

High-resolution is becoming the most important keyword in audio today, and in order to faithfully reproduce its high-quality sound, it is necessary to select a standard that is compatible with it.

3. Whether or Not a DAC Is Installed

A DAC (Digital Analog Converter) is a circuit that converts digital signals input to an amplifier into analog signals for output. This type of DAC is considered optimal for playing back high-resolution sound sources distributed by various media on a PC from which they have been downloaded.

4. Connecting to a Network

If you want to connect to a network like a smartphone or PC, you must choose a Wi-Fi-compatible model. Of course, for wireless use over a short distance, a Bluetooth-compatible model will work fine. Also, by using a model with the AirPray function, you can play content that can be played on your iPhone or iPad over a network.

What Are Magnetic Materials?

Magnetic materials are materials that utilize their strong magnetism to perform various functions.

Magnetic materials can be broadly classified into two types. One is a magnet attached to a metal such as iron, which is a hard magnetic material. The other is a type of material that becomes a magnet when a magnetic field is applied to it, but is no longer a magnet when the magnetic field is removed, and is a soft magnetic material.

Hard magnetic materials do not start out as magnets, but become magnets when they are magnetized by applying a momentary magnetic field. It is also possible to lose magnetism by applying an alternating magnetic field or by raising the temperature above the Curie temperature (Tc) to make the spontaneous magnetization zero, which is called demagnetization.

The residual flux density (Br [T]) of a magnet is the magnetic force it exhibits when the magnetic field is removed. On the other hand, soft magnetic materials show almost no magnetic force after the magnetic field is removed, and Br is close to zero.

The difference between hard and soft materials is not a difference in the physical hardness of the materials, but a difference similar to that between a hard and soft head in the sense of whether the material is amenable to the environment or not.

Classification of Magnetic Materials

Both hard and soft magnetic materials are classified as ferromagnetic, and the specific magnetic permeability, which expresses how easily a material is magnetized, is much higher than 1. The term magnetic material refers to ferromagnetic materials. In contrast to ferromagnetic materials, there are also paramagnetic and antimagnetic materials, which have a specific permeability of around 1 and are hardly magnetized.

The BH curve is a typical representation of the characteristics of magnetic materials. It is a curve that depicts the magnetic field H [A/m] on the horizontal axis and the magnetic flux density B [T] on the vertical axis when the magnetic field given to magnetic materials is varied. The intercept between the curve and the abscissa is called the residual flux density (Br).

Depending on the altitude of the magnetic metal, it can be broadly classified into hard magnetic materials, soft magnetic materials, and magnetostrictive materials. Major applications include home appliances, motors, generators, magnetic disks, and everything from the home to the manufacturing floor. Since the performance of magnetic materials varies greatly depending on the environment and physical conditions, it is necessary to select the most suitable magnetic materials for the environment in which they will be used.

Types of Magnetic Materials

Soft magnetic materials include iron, silicon iron, permalloy, soft ferrite, sendust, permendur, electromagnetic stainless steel, amorphous, and nanocrystalline.

Hard magnetic materials include hard ferrites, alnico magnets, samarium-cobalt magnets, neodymium magnets, and samarium-iron-nitrogen magnets. Ferrite is a magnetic material consisting mainly of iron oxide mixed with barium, strontium, cobalt, nickel, manganese, etc., and sintered at 1,000 to 1,400 ºC.

Typical examples are as follows:

1. Rare Earth/Rare Earth Magnets

Rare earth magnetic materials are magnetic materials used mainly in automotive parts, motors and electronic devices. In particular, neodymium-iron magnetic materials are hard, durable, and have a very large magnetic energy product.

However, these magnetic materials tend to lose their magnetism at high temperatures, so particular attention should be paid to the thermal environment in which they are used. Samarium-cobalt magnets, which are also rare earth magnets, have slightly less magnetic force than neodymium magnets, but they have great durability against heat and rust, so they can be used under high temperatures where neodymium materials are not suitable.

2. Alnico Magnet

Alnico magnetic materials are cast materials made primarily of aluminum, nickel, and cobalt. This material is resistant to temperature, and its hardness and strength make it difficult to crack, and it is mainly used in instruments and other devices. However, its coercive force is lower than that of other materials, so it easily loses its magnetic force due to external shocks.

3. Ferrite Magnet

Ferrite magnets are mainly made of powdered iron oxides and are extremely versatile magnetic materials. Applications include small motors, speakers, magnetic tapes, etc. Since it is relatively inexpensive for its high coercive force, it is used in products for mass production. Since it is manufactured from powder, it is brittle against impact and is not suitable for cutting or drilling.

Examples of Applications for Magnetic Materials

Hard magnetic materials are used in motors, speakers, and headphones. Soft magnetic materials are used in solenoid valves, various sensors, televisions, videos, and personal computers.

Properties of Magnetic Materials

The two major property categories of magnetic materials are isotropic and anisotropic. These properties depend on whether a magnetic field is applied or not during the process of making magnetic materials, and anisotropic magnetic materials retain a stronger magnetic force.

What Is a Server?

A server is software or a computer that acts as the main administrative base for computer systems. Administrative controls can be run more efficiently within a server interface There are many types of servers, each with different functions. Every system in its current state cannot operate without a server.

Types of Servers

1. Web Server

A web server is a server that stores information (e.g., HTML and image files) for displaying a typical web site. It is essential to operate a website because it needs to return appropriate information in response to user requests (i.e., clicks on a website).

2. Mail Server

A mail server is used to send and receive e-mail. In most cases, there are two separate servers, one for sending and the other for receiving mail. There are various reasons for the division into two, but the main reason is that the servers perform very different responses.

The outgoing server is responsible for properly sending the user’s input to the receiving server, and the receiving server is responsible for properly receiving the content sent by the other outgoing server. The outgoing server is called SMTP (Simple Mail Transfer Protocol) and the receiving server is called POP (Post Office Protocol).

3. Database Server

A database server is a server that returns information that has been stored by users, such as text sent and received via web servers and mail servers, and categorizes it appropriately.

4. DNS Server

A DNS (Domain Name System) server is a server that connects your IP address to your domain. Users always have an IP address, and the DNS server associates that IP address with a domain. This conversion makes the URL understandable.

5. FTP Server

FTP (File Transfer Protocol) servers, also known as file transfer protocols, are used primarily by web sites to send and receive files within a site.

In the past, it was only used for sending (sending HTML files to display a web site), but it also retains the ability to receive files if you want to receive them as files (e.g., image files).

6. SSH Server

The SSH (Secure Shell) server is an encryption server. It is used to prevent information leakage by encrypting personal information.

Server Rental

Servers, by their very nature, must be able to hold large amounts of data and operate at high speeds. If a website server is maintained by an individual, it is difficult to determine how much access is expected, so a rental server is generally used to gather the required data.

What Is a Scanner?

A scanner is a device that reads information by scanning an object with light.

Types of Scanners

There are two types of scanners: those that scan two-dimensional information and those that scan three-dimensional information.

Scanners that scan two-dimensional information generally refer to image scanners that scan printed materials as image data. Typical examples are flathead scanners and sheet-fed scanners (ADF scanners, auto-feed scanners), which are widely used to store and manage documents, photographs, and graphics.

Other types of scanners specialize in reading specific image information. These include passport scanners, business card scanners, film scanners that digitize negative and positive photo film, overhead scanners (book scanners, stand scanners) that scan books without cutting them (non-destructive self-catering), and pen scanners that convert text in books into text data. Barcode scanners (barcode readers) that read barcode information such as QR codes are also a type of image scanner.

Scanners that scan three-dimensional information are broadly defined as 3D scanners, and are used to read the physical shape of three-dimensional objects. Non-contact 3D scanners, which are widely used in industry, can be broadly classified into optical scanners and CT scanners.

Optical scanners are suitable for capturing data on the geometry of parts that are clearly visible from the outside. They are used for designing, dimensioning, and inspecting parts in the automotive, aerospace, defense, and manufacturing industries, as well as for surveying topography and large structures in the civil and construction industries. During optical scanning, the light that is irradiated onto the object can be either laser or patterned light.

CT scanners can nondestructively read the internal shape of an object based on the amount of radiation transmitted, and are widely used in the medical field as well as for the inspection of defective parts inside products.

Storage and Management of Scan Data

Conventionally, scanner data has been stored and managed on a PC connected to the scanner. Today, however, network scanners are widely used to store and distribute data without the need to operate a PC by connecting the scanner itself directly to a network.

What Are Drive Mechanism Components?

Drive specifically refers to the motion of rotating a motor and transmitting it as power to rotate a conveyor.

In addition to rotation, it can also convert rotational motion into linear motion and vice versa. A familiar example is the automobile. The rotation of the engine of an automobile is transmitted to gears to rotate the tires and convert them into forward or backward motion, which is also driving.

In this article, the drive mechanism is referred to as the drive mechanism and the parts that drive it are referred to as the drive components.

Types of Driving Components

Since the nature of the drive mechanism varies greatly depending on the different drive components, we will first introduce some typical drive components.

1. Belt

A belt is a component that transmits power using frictional force. Types of belts include flat belts, which are often used for conveyors and other transportation, timing belts, which excel in positioning accuracy, and V-belts, which are suitable for high-speed rotation.

2. Gears

Gears are parts that transmit power by meshing teeth made up of peaks and troughs. Types of gears include spur gears with parallel teeth cut into a cylinder, racks with teeth cut into a bar-shaped object, and bevel gears with teeth cut at an angle like an umbrella.

3. Cam

There are plate cams, in which a disk with a mixture of curves is attached to a rotating shaft, and cylindrical cams, in which a groove is cut in a cylinder.

Types of Drive Mechanisms

The following types of drive mechanisms are available:

1. Belt Mechanism (Chain Mechanism)

This mechanism uses a belt (or chain) to transmit rotation and change the speed or torque to make another rotation. It is used to rotate a cutting tool or shaft, or to transport objects.

2. Gear Mechanism

This mechanism uses gears to transmit rotation, change the speed or torque by changing the gear ratio of the gears, change the direction of rotation by using bevel gears, or convert rotational motion to linear motion by using racks.

3. Cam Mechanism

A cam mechanism transmits rotation and converts it into reciprocating or oscillating motion, or conversely converts reciprocating motion into rotational motion.

In an automobile engine, the reciprocating motion of the piston caused by the explosion of gasoline is transmitted to the crankshaft, which is a cam shaft, and converted into rotational motion.

What Are Surge Countermeasures?

Surge countermeasures are measures taken to prevent circuit breakage when a surge occurs.

While the term surge is commonly associated with sudden rises or spikes in stock prices or prices, in industrial applications, it usually refers to a sudden rise or spike in voltage or current. Surge countermeasures are taken by using surge countermeasure components, which are often referred to as surge absorbers or surge protectors.

There are two main types of surge protection devices: semiconductors and discharge tubes. A typical semiconductor type device is the varistor (ZnO), which derives its name from variable and resistor. Functionally, a varistor is a non-linear resistive element whose resistance changes in response to voltage.

A varistor can be seen as an element that starts the sudden flow of current when a certain voltage is applied. Additionally, there are three semiconductor types: the diode type, which uses a PN junction, and the thyristor type. On the other hand, the discharge tube type are known as arresters (lightning arresters), and they can further be categorized as gap arresters and micro-gap types. The gas-filled discharge tube type is called a gas arrester or gas discharge tube (GDT).

Types of Surge Countermeasures

The surge countermeasures required depends on the type of surge. Surge types can be roughly classified into lightning surge, open/close surge, load dump, and ESD (electrostatic discharge). Open/close surges are caused by the back electromotive force of the coil when the current is suddenly interrupted by a switch. Load dumps, on the other hand, are large surges that occur in automobiles due to battery disconnection.

Examples of Surge Countermeasures

A typical surge countermeasure using a varistor, a semiconductor device, is to connect it in parallel with the protected circuit so that current will flow to the varistor when a surge voltage above a certain level is applied, thereby protecting the protected circuit side. In other words, it is a protection circuit by forming a bypass circuit.

The discharge tube type is said to be more durable than the varistor type, but it is difficult to use the discharge tube type by itself because the discharge tube phenomenon known as continuous current can cause electricity to continue flowing.

What Are Electromagnetic Countermeasures?

Electromagnetic Countermeasures are measures taken to prevent effects of electromagnetic radiation.

Electromagnetic waves are waves that travel through space where electricity flows, where radio waves fly, and where magnetic fields are generated, interacting with each other.

Electromagnetic waves are divided into ionizing and non-ionizing radiation. The boundary between them is 3000 THz, and ionizing radiation is what is usually referred to as radiation. The frequency range of electromagnetic waves covered by guidelines is from 10 kHz to 300 GHz. The lower and higher frequencies are divided into two categories: low frequency and high frequency.

Since the properties of electromagnetic countermeasures differ depending on the frequency, classification by frequency and countermeasures are necessary. Examples of low-frequency waves are power lines and electrical appliances, which operates at frequencies of is 50~60 Hz and wavelengths of 5000~6000 km. Examples of high-frequency waves include cell phones and microwave ovens, which have frequencies ranging from 800 MHz to 3 GHz and wavelengths from 10 to 40 cm. Electromagnetic waves are measured in terms of power density (mW/cm) and absorbed rate (SAR) (W/kg).

In terms of magnetic field strength, the global average of the geomagnetic field is about 46 μT. The World Health Organization (WHO) states that magnetic fields of 500 μT or less are not considered to have any biological effects. 

Guidelines for electric and magnetic fields have been established by organizations such as the WHO and the International Commission on Non-Ionizing Radiation Protection (ICNIRP),. Electromagnetic countermeasures are achieved by absorbing, shielding, and attenuating outgoing and incoming electromagnetic waves.

Types of Electromagnetic Countermeasures

Not all frequencies of electromagnetic waves can be shielded, particularly at low frequencies.

Various types of electromagnetic countermeasures are used. Ferrite cores, capacitors, and common mode choke coils are used as filtering components to attenuate electromagnetic noise, while conductive tape, metal mesh, and shielding gaskets are used to shield incoming and outgoing electromagnetic waves.

In addition, electromagnetic shielding for the housings of home appliances and other products involves the application of metallic materials, electroless shield plating, vacuum deposition, coating with conductive paints, and the attachment of conductive fibers. Aprons made of conductive fibers are commercially available as a method to shield electromagnetic waves to the human body.

Principle of Electromagnetic Shielding

The principle of electromagnetic shielding is to attenuate electromagnetic wave energy based on the three properties of reflection, absorption, and multiple reflection of electromagnetic waves. Attenuation minimizes the adverse effects on the human body and equipment. Shielding performance is usually expressed in decibels, which is the logarithm (log) of the electric field strength after shielding / electric field strength before shielding or the magnetic field strength after shielding / magnetic field strength before shielding multiplied by 20 (in dB).