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What Is a High Frequency Relay?

A high frequency relay is one of the elements that switch high-frequency signals.

Since high frequency relays generally do not have connectors, they are used by soldering, and their high frequency characteristics are greatly affected by the substrate. When relays are used in high- frequency circuits, there are also issues of isolation (signal leakage between contacts (circuits) when the contacts are open) and insertion loss (signal loss when the contacts are closed).

Uses of High Frequency Relays

High frequency relays are used in devices that have a circuit called a high frequency circuit. In order to control high-frequency signals, a relay specialized for high frequency is needed, not an ordinary relay.

Examples include cell phone base stations, broadcasting equipment, measuring instruments, and radio equipment. Another application is wireless LAN and Bluetooth, which are widely used in homes. In both cases, the relay plays the role of smoothly switching signals inside various types of equipment.

Principle of High Frequency Relays

High frequency relays have the same structure as general relays.

1. Principle of Relay

In a relay, when a small amount of electricity flows through a coil wound around an iron core, an electromagnet draws the iron pieces together, causing them to contact each other and connect the circuit. When the electricity between the terminals is cut off, the magnetic field generated in the coil is dissipated and the electrical equipment stops operating.

When relays are used in high-frequency circuits, isolation and insertion loss become problems.

2. Isolation

Isolation corresponds to the resistance between output terminals when the relay is off. At high frequency relays, signal leakage occurs even when the relay is off. Isolation is a parameter that indicates the degree of this signal leakage.

The higher the frequency, the greater the leakage, and the smaller the value of isolation itself tends to be. This can cause interference between circuits.

3. Insertion Loss

Insertion loss, also called insertion loss, refers to the signal loss between contacts that occurs when the contacts are closed. The higher the frequency, the greater the signal loss between contacts (circuits), making it impossible to transmit signals accurately and causing heat to be generated.

In other words, it is important that there is little signal leakage between contacts when they are open and little signal loss when they are closed, even when the signal frequency increases.

4. Return Loss

When there is an impedance change in the middle of a signal path, a phenomenon called reflection occurs, in which part of the signal does not reach the receiving side but returns to the transmitting side.

The degree of signal reflection is called return loss, which is expressed as the ratio of input power to reflected power. Another indicator of the degree of reflection is VSWR (Voltage Standing Wave Ratio): the closer the VSWR value is to 1, the less reflection there is, meaning that it is a good characteristic.

Relays used in high-frequency circuits require high frequency characteristics in addition to general relay characteristics, so they must have high isolation and low insertion loss as described above. In addition, return loss, which indicates the degree of signal reflection, must be large, VSWR must be small, and characteristic impedance, which indicates the value of resistance, must be appropriate.

Other Information on High Frequency Relays

High-Frequency Circuits

High-frequency circuits refer to electronic circuits whose operation at high frequencies differs from that at low frequencies. Circuits that handle electronic signals with frequencies ranging up to several GHz, such as wireless LAN, are high-frequency circuits.

When electronic signals are at high frequencies, it is necessary to take into account that the current and voltage levels of the signals are different at different locations in the electronic circuit. Circuits that handle this behavior are called distributed constant circuits.

What Is a Magnetic Field Sensor?

A magnetic field sensor is a sensor that detects the earth’s magnetism (geomagnetism).

There are two types: a 2-axis type that can detect the XY axis and a 3-axis type that can detect the XYZ axis. The 2-axis type can be used on flat terrain, but the 3-axis type cannot accurately detect the geomagnetic field unless it is used on a slope.

Uses of Magnetic Field Sensors

Magnetic field sensors are used to detect direction. They are used as electronic compasses in GPS devices for mountain climbing and are also used in smartphones and car navigation systems to measure the orientation of the device on a map.

The 2-axis type is used in automobiles to detect the XY axis, while the 3-axis type, which can detect the XYZ axis, should be used in aircraft and other vehicles capable of three-dimensional motion such as pitch and yaw.

Principle of Magnetic Field Sensors

A magnetic field sensor measures the magnetic force in the X-axis, Y-axis, and in the case of a 3-axis sensor, in the direction of the Z-axis, and calculates the azimuth.

There are three types of magnetic field sensors: Hall sensors, MR (Magneto Resistance) sensors, and MI (Magneto Impedance) sensors are the most common types of magnetic field sensors. The principle of each type of sensor is explained below.

1. Hall Sensor

The magnetic flux, which is the perpendicular component of the magnetic field, gives an electromotive force to the Hall element, which is then sensed as geomagnetism. The Hall effect is used to measure the magnetic flux density, and after passing through an amplification circuit, the sensor outputs a voltage proportional to the magnetic flux density. It is characterized by its ease of use.

2. MR Sensor

In MR sensors, the magnetic flux, which is the horizontal component of the magnetic field, ohms the MR element, which is then sensed as the geomagnetic field. It differs from a Hall sensor in that it measures the magnitude of the geomagnetic field by utilizing the change in the electrical resistance of the MR element caused by the magnetic field.

Because of its higher sensitivity and lower power consumption compared to Hall sensors, it is used more frequently and is often used for geomagnetic sensing applications such as electronic compasses, motor rotation, and position sensing applications.

3. MI Sensor

MI sensors use wires made of a special material called amorphous wire, which does not have a crystalline state. When a pulse current is applied to the amorphous wire in the presence of geomagnetic field, the MI effect is generated and the geomagnetic field is detected using the change in magnetic impedance. The MI effect is more than 10,000 times more sensitive than a Hall sensor, so even minute changes in the geomagnetic field can be measured with high accuracy.

The MI effect is a phenomenon in which the impedance of a magnetic material changes with high sensitivity in an external magnetic field when a high-frequency current that causes a skin effect is applied to the magnetic material.

The skin effect refers to the effect that when a high-frequency current flows through a conductor, the current density increases near the surface of the conductor and decreases as it moves toward the interior.

Other Information on Magnetic Field Sensors

1. Hall Element

A Hall element is a magnetic sensor that uses the Hall effect. The Hall effect is a phenomenon in which an electromotive force is generated in a direction perpendicular to the current and the magnetic field when a magnetic field is applied perpendicular to the electrons flowing through a material.

The charged particles that carry the current are subjected to the Lorentz force under the influence of the magnetic field, which causes a bias in the charge within the material. At this time, a potential difference is generated within the material, resulting in an electromotive force.

2. MR Sensor Element

MR sensor elements are magnetic sensor elements that utilize the magnetoresistive effect (MR effect), a phenomenon in which the resistance value changes when the magnetic field is changed.

Electrons have two spin states called up-spin and down-spin. As electrons move through a ferromagnetic material, the scattering probability within the magnetized material fluctuates when the spin state of the electrons changes up or down. This is what causes the MR effect.

What Is a Motor Driver?

A motor driver is a device that controls the drive related to motor rotation. Combined with a computer such as a microcontroller, it controls the timing and speed of motor rotation by applying the appropriate voltage and current.

The motor driver IC, which is the heart of the motor driver, is very small, so it has the advantage of reducing the mounting area compared to building a separate motor control circuit by combining stand-alone components. In addition, some motor drivers are equipped with protection functions against overcurrent and overheating, enabling users to drive motors safely.

Uses of Motor Drivers

The appropriate motor driver is selected based on the type of motor. Typical motors include brushed DC motors, brushless motors, stepper motors, and linear motors.

DC motors are simple, inexpensive, and versatile motors used in a variety of applications, including home appliances such as washing machines. They are also used in linear motors where the magnetic poles are changed by changing the direction of the current. The linear bullet train is a synchronous linear motor, and the motor driver is used to control the propulsion by changing the magnetic poles of the rails.

Principle of Motor Drivers

The principle of operation of a motor driver depends on the type of motor being controlled. Specifically, the configuration of the bridge circuit for switching the energization differs.

For example, a DC motor driver controls the direction of rotation by switching the direction of the current flowing to the electromagnets. For example, applying current in the opposite direction to a motor rotating at high speed will brake the rotation and thus reduces the speed of rotation.

In this case, a half-bridge circuit is constructed using multiple transistors. The direction of current flow is determined by the combination of transistors. In brushless motors and stepping motors, it is the half-bridge circuit that controls the current corresponding to the number of coils (number of phases) drawn from the motor.

For brushless motors, there are single-phase and three-phase circuits, and for stepping motors, there are two-phase and five-phase circuits. In addition, there is another method to control the rotation speed by combining PWM control, which modulates the width of the pulse voltage.

Other Information on Motor Drivers

Brushless Motors and Stepping Motors

The motor driver market can be broadly divided into the aforementioned DC motors (with brushes), brushless motors, and stepping motors. Brush DC motors are easy to handle because they can be easily driven by applying voltage, but they are cost-prohibitive in a market where many types of motors are available.

Brushless motors are used in PC cooling fans and other applications that require relatively efficient operation and high reliability. Stepping motors, as the name suggests, are characterized by their ability to provide sophisticated control of motor rotation, and are used in industrial applications such as high-precision actuator control for factory automation, as well as in consumer devices such as printers.

In the automotive market, represented by the recent shift to EVs, highly efficient operation of motors using motor drivers is indispensable, because motors must be able to handle a wide range of motor control, from high torque at low speeds to high speeds, and the life of the battery until discharge directly affects the driving distance. To achieve this, PWM control of the motor driver using a microcontroller is an essential technology, along with inverter control technology for high power output for in-vehicle use.

Although motor drivers are a technical field in which even beginners can make their own motor drivers using single components, full-scale control requires an understanding of the principles of motor operation, control algorithms using a microcontroller, and software support.

Therefore, some of the latest motor drivers are equipped with dedicated application software to make it easy for users to use them.

What Is a Barcode Reader?

A barcode reader is a device that optically reads the numbers and characters represented by a barcode and picks up the information contained in the barcode.

Most barcode readers on the market today consist of a light source using an infrared laser, a part that receives the reflected light, and a part that sends the scanned data to a PC.

Uses of Barcode Readers

Barcode readers are used to read barcodes on products to manage the distribution of goods in the logistics industry. Barcode readers are also indispensable for other purposes, such as managing drugs in the medical field and cash registers in supermarkets and convenience stores, in order to improve convenience.

QR codes, which are familiar through smartphone applications, are also a type of 2D barcode, and there are barcode readers on the market as well as smartphones that can read these codes.

Principle of Barcode Readers

The principle of barcode readers is based on the physical phenomenon that laser beams emitted on the black areas of a monochrome line are absorbed and only laser beams emitted on the white quiet zone are reflected. When a laser beam is applied to a barcode and scanned, the light receiving element recognizes the presence or absence of reflected light and reads the line information of the barcode as an analog signal.

Next, the weak analog waveform acquired by the light receiving element is amplified and converted into a digital signal, with the values exceeding a certain threshold being set to 1 and other values to 0, and decoded.

At this time, care must be taken not to irradiate the laser at a right angle to the barcode. If the laser is irradiated at a right angle to the barcode, the barcode will receive strong direct reflected light, which will cause its output to be too large compared to the other diffuse reflected light, and a clean analog waveform will not be obtained. For this reason, many barcode readers must be set up so that the laser is obliquely incident on the barcode.

Types of Barcode Readers

There are several types of barcode readers in terms of the codes they read and the way they read them.

1. Read Code

• 1D Barcode Reader
  There are two types of barcode readers: “laser engine type,” which reads barcodes by irradiating them with laser light, and “CCD engine type,” which reads barcodes by irradiating them with LED light.
• 2D Barcode Reader
  There are “long range type” that can read from close range to long range, “high performance CMOS type” that have high resolution and are resistant to blurring, and “low cost CMOS type” that are inexpensive but vulnerable to camera shake.

2. Reading Method

• Pen Scanner
  Scanning is done by tracing with a pen.
• Fixed Scanner
  The reader is fixed in a specific position.
• Card Reader
  Reads barcodes on cards.
• Hand-Held Scanner
  Holds the reader in the hand and touches the reading area.

Other Information About Barcode Readers

1. Barcode Reader Reading Accuracy

The reading accuracy of a barcode reader is determined by the “read rate” and the “false read rate.” Read rate is defined as the number of successful reads relative to the number of barcode scans performed. For example, if the number of barcode scans is 1,000 and the number of successful reads is 995, the read rate is 99.5%. The false read rate is similarly defined by the number of false reads relative to the number of times read.

The read rate varies depending on the quality of the barcode label, the resolution of the barcode reader, the number of times it is read, and the decoding algorithm. Of these factors, the quality of the barcode label is the most significant.

If the barcode is free of dirt or scratches, the width of the code is within specifications, and the contrast is high, it can be read at a read rate close to 100%. However, the actual barcodes to be read are rarely clean, and manufacturers need to be able to read barcodes at a high read rate, even under adverse conditions.

2. Barcode Reader Interface

The communication interface used to read barcode reader data into a PC includes USB, RS232C, and PS/2 wired interfaces, as well as products with wireless connectivity, such as Bluetooth. Recently, the use of the USB type, instead of RS232C or PS/2, has been increasing along with the increased use of thin notebook PCs. Note that some USB type products are compatible with some PC operating systems, while others are not.

3. About Fixed Barcode Readers

Fixed barcode scanners are important devices in the manufacturing and logistics industries. Built into manufacturing equipment or installed in a fixed position, they use optical sensors or laser technology to read the barcodes of products or packages automatically as they flow down a conveyor. Depending on the reading distance and angle, short-range scanners and long-range scanners are available for efficient production control and tracking.

What Is a Switching Power Supply?

A switching power supply is a device that supplies DC power using a switching regulation method among DC power supplies.

General power supplies can be roughly classified into two types: the linear type, which is low-cost but heavy due to its simple circuit structure, and the switching type, which is compact due to the use of ICs. Due to their respective characteristics, the linear type is used for simple AC adapters, while the switching type is used for supplying power to electronic components in facilities.

Uses of Switching Power Supplies

Switching power supplies are used to supply power to industrial information equipment. In recent years, as electronic equipment has become more sophisticated, AC adapters have shifted from heavy linear systems to compact switching systems.

Furthermore, with the spread of USB power supplies, switching power supplies has become an indispensable component for supplying power to compact electronic equipment. In the industrial field, switching power supplies are widely used as components that stably supply DC power to drive control electronic components such as solenoid valves and sensors in automated equipment.

Principle of Switching Power Supplies

A switching power supply is a device that uses an AC power source such as 100 VAC as input, converts it to a DC power source such as 5 to 30 VDC, and stably supplies it.

The circuit configuration of a typical switching power supply is as follows:

• Input Rectification and Rectifying Circuit
  The input AC power supply is smoothed as much as possible.
• Switching Circuit
  Switching from AC power to DC power is possible.
• Output Rectification and Rectifying Circuit
  Smoothes the distorted DC power supply after conversion.
• Control Circuit
  Controls output voltage and output power.

This configuration makes it possible to obtain a stable DC power supply with constant voltage.

Other Information on a Switching Power Supply

1. Difference Between a Rectifier and a Power Supply

Rectifier is a generic term for an element that has the property of conducting current in one direction, while power supply is a generic term for a power source. A rectifier can be said to be an element that converts an AC power source into a DC power source. It is a diode or switching device that allows the current to flow in one direction.

There are two types of rectification: half-wave rectification and full-wave rectification.

Half-Wave Rectification
In AC circuits, positive and negative currents flow alternately, and “half-wave rectification” removes either the positive or negative current. The circuit configuration is simple and low-cost, but the efficiency is low and it cannot handle large currents.

Full-Wave Rectification
Full-wave rectification is a method that takes both positive and negative currents and changes them to a unidirectional current. This method is mainly used in switching power supplies. Compared to half-wave rectification, full-wave rectification is more efficient, and pulsation can be suppressed to a smaller degree.

Full-wave rectification includes a method that uses two diodes and a bridge circuit method that combines four diodes. Since the current after these rectifications is unstable, the output from the rectifier is combined with a circuit, such as a capacitor, for smoothing to remove pulsation and function as a power supply.

2. Causes of Failure of Switching Power Supply

There are “external factors” and “internal factors” that cause failures in switching power supplies.

Failure Due to External Factors

• Physical destruction
• Sudden influx of high voltage or noise due to lightning
• Circuit short-circuit failure due to dust or moisture intrusion
• Destruction of various parts of the circuit due to chemicals or corrosive gases

In particular, the sudden application of high voltage due to lightning strikes destroys each element and other electronic components inside the power supply. To prevent these failures, it is effective to install protective circuit products such as surge killers.

Failures Due to Internal Factors
Internal factors are caused by the deterioration or failure of electrolytic capacitors, cooling fans, semiconductor components, etc. The usable life of a power supply varies greatly depending on the environment in which it is used, the time it is used, and other factors.

What Is a DIN Connector?

DIN connectors are connectors that adhere to the DIN standard, established by German industry. These connectors are typically round, with a standard diameter of 13.2 mm, although there are variants known as two-piece connectors. Mini-DIN connectors are smaller, round connectors with a 9.5 mm diameter.

Circular DIN connectors range from three to several pins. Some older models, like speaker DIN connectors, feature two pins. These connectors usually lack a locking mechanism, making them prone to disconnecting if pulled forcefully. Both male and female types exist, connecting based on the plug’s shape.

Uses of DIN Connectors

DIN connectors are primarily used in audio equipment for stereo signal input and output, connecting devices like recorders, remote controls, car audio systems, and speakers. They are also found in electronic musical instruments, computers, televisions, video game consoles, and microphones. In personal computers, two-piece connectors facilitate the connection between electronic circuit boards. These square-shaped connectors come in various pin counts and pitches.

Principle of DIN Connectors

DIN connectors comprise a male plug and a female socket. Each connector consists of a housing and contact parts. The housing and contacts are designed with slightly different shapes to ensure a secure connection between male and female connectors. When connected, the contacts align, establishing an electrical connection.

Each pin in circular DIN connectors transmits a separate signal, enabling complex connections like those in game consoles, which carry audio, ground, video, and voltage signals.

Structure of DIN Connectors

A DIN connector includes both housing and contact parts.

1. Housing Part

The housing encases the contacts and is typically made from an insulating material like plastic to protect the contacts.

2. Contact Part

The contact part is responsible for establishing the electrical connection upon connector engagement. Depending on the connector type, a shell or an eyelet might be used for additional protection or connection.

Types of DIN Connectors

DIN connectors vary in shape, including circular, speaker, small circular, and two-piece connectors. Circular connectors are 13.2 mm in diameter and range from 3 to several pins, used in applications such as audio equipment, game consoles, and PC keyboards. Speaker DIN connectors, which have 2 pins, were traditionally used for speakers and are designed with distinct pin shapes to prevent misalignment.

Other Information on DIN Connectors

DIN Standard

The DIN standard, defined by the German Standards Institute, covers not just connectors but also specifications for products like car navigation systems. Germany actively promotes standardization to advance business and society, allowing proposals from various entities, including companies, research institutes, and consumers.

What Is a Film Capacitor?

A film capacitor is a capacitor that uses plastic film as a derivative. The technology traces its roots back to paper capacitors invented in the late 19th century. In paper capacitors, oil or paraffin paper is clipped onto aluminum foil and rolled.

The type that is rolled by depositing metal directly onto paper is called a metalized paper (MP) capacitor. Film capacitor was developed in the 1930s based on these technologies.

Film capacitor is classified into foil electrode type and vapor-deposited electrode type (metalized film type) according to the structure of the internal electrodes, and further into wound type and laminated type, inductive type, and non-inductive type according to the difference in structure.

Uses of Film Capacitors

Film capacitors are used in a wide variety of products from consumer products to industrial equipment. Examples of consumer products are home appliances such as refrigerators and in-car electronic equipment such as car navigation systems, car audio systems, and ETC systems. Examples of industrial equipment include power electronics equipment.

Film capacitors are characterized by high insulation resistance and high safety. They are also non-polarized, have excellent high-frequency characteristics, and have good temperature characteristics. In addition, film capacitors have high capacitance accuracy and a long service life.

However, film capacitors are larger than multilayer ceramic chip capacitors. Therefore, film capacitors tend to be used in voltage and capacitance ranges that cannot be covered by ceramic capacitors, as well as in high-performance and high-precision crises.

Principle of Film Capacitors

Capacitors are electronic components that store and release electricity. When voltage is applied between opposing conductors, electrostatic induction occurs in the insulator or space between them. The electrostatic induction action causes dielectric polarization in the insulator, which charges the battery.

Film capacitors use a film as the inductor. Film capacitors can be classified into several categories according to the construction and structure of the internal electrodes.

1. Foil Electrode Type Film Capacitors

These are wound film capacitors in which a plastic film is wound over a metal foil that serves as the internal electrode. The metallic foil is made of aluminum, tin, or copper.

There are two types of foil-electrode film capacitors: inductive and non-inductive. The inductive type is wound with a lead wire attached to the internal electrode, while the non-inductive type has a lead wire or terminal electrode attached to the end face. The inductance component of the non-inductive type can be smaller than that of the inductive type, resulting in superior high-frequency characteristics.

2. Evaporated-Electrode Film Capacitors

This is a type of film capacitor in which the internal electrode is made by vapor-depositing metal onto plastic film. Aluminum or zinc is used as a metallic material. Since the vapor-deposited film is very thin, this type of capacitor can be made smaller than the foil electrode-type film capacitors.

Other Information on Film Capacitors

1. Polarity of Film Capacitors

Film capacitors do not have polarity. In other words, film capacitors are non-polarized capacitors. There are two types of fixed capacitors: non-polarized capacitors and polarized capacitors.

Non-Polarized Capacitor
A non-polarized capacitor is a capacitor whose terminals do not distinguish between positive and negative. It does not matter which terminal is positive. The polarity of the voltage applied to the terminals is not regulated. Non-polar capacitors can be used directly in AC circuits.

Film capacitors are one of the mainstream nonpolar capacitors. Other non-polar capacitors include ceramic capacitors, paper capacitors, mica capacitors, and air capacitors.

Polarized Capacitors
A polarized capacitor is a capacitor with two terminals, one of which is positive. If the polarity of the terminals is used incorrectly, the capacitor will be damaged. 

2. Film Capacitors and Audio

Audio equipment can be self-made or customized to one’s taste in sound. Multiple factors affect the quality of sound, but the parts used also affect the sound quality. Capacitors are one of those parts.

The characteristics required of capacitors used in audio amplifiers include the following:

• Good high-frequency characteristics
• Low harmonic distortion
• Low so-called squeal

Compared to electrolytic capacitors, film capacitors are superior in the above characteristics. In terms of sound quality, film capacitors have better sound transparency and resolution than electrolytic capacitors.

What Is a Silicon Carbide (SiC) MOSFET?

SiC MOSFET is a MOSFET that uses a silicon carbide (SiC) MOSFET, a compound semiconductor, instead of the conventional Si substrate.

MOSFETs are used for on/off switching, amplifiers, and other applications. By using SiC, a compound semiconductor, as the semiconductor substrate material, it is possible to reduce the resistance when voltage is applied compared to a conventional silicon carbide (SiC) MOSFET.

As a result, switching loss during turn-off,and power loss during power operation can be reduced. This can improve the performance of the semiconductor chip and reduce the cooling capacity required during transistor operation, leading to downsizing of the product itself.

Uses of Silicon Carbide (SiC) MOSFETs

SiC MOSFETs are used in many semiconductor products, such as relays, switching power supplies, and image sensors in the field of power electronics. SiC MOSFETs are also used in communication equipment in many cases.

When selecting a silicon carbide (SiC) MOSFET, the operating conditions of the product application must be considered, i.e., absolute maximum ratings, electrical characteristics, package use and size, etc.

Principle of the Silicon Carbide (SiC) MOSFETs

Silicon carbide (SiC) MOSFETs can achieve a MOSFET structure that allows low ON resistance and low-loss operation during turnoff, while maintaining a similar level of withstand voltage. This is because the active layer thickness can be reduced because the transistor is made of SiC substrate, which has properties of band gap energy about 3 times higher and breakdown field strength about 10 times higher than that of Si substrate.

A silicon carbide (SiC) MOSFET has a stacked structure of p-type and n-type semiconductors. Usually, the n-type semiconductor is stacked on top of the p-type semiconductor. The drain and source electrodes are attached to the n-type semiconductor, and the oxide insulating layer and gate electrodes are attached between the n-type semiconductors. In addition, SiC (silicon carbide), a compound semiconductor, is used as an epi-substrate for the silicon wafer of the body.

In a MOSFET, applying a positive voltage to the gate causes a current to flow between the source and drain. In this case, a silicon carbide (SiC) MOSFET, which uses SiC in the silicon wafer, can operate with a larger voltage and current between the source and drain than a MOSFET that uses only Si. Since the concentration of impurities in the semiconductor can be increased, losses can be reduced and the size of the MOSFET can be made smaller.

Other Information on Silicon Carbide(SiC) MOSFETs

1. Distinction Between Silicon Carbide (SiC) MOSFETs and IGBTs

IGBTs are transistors used for applications in the high-power range, which are difficult to handle with ordinary Si MOSFETs, but recently SiC MOSFET devices are being used in this range. SiC MOSFET devices are being used in this area because SiC has a large band gap energy, which allows it to operate at higher temperatures than IGBTs. Another reason is that SiC MOSFETs can overcome the problem of large switching losses in the subsequent bipolar transistor in the case of IGBTs.

In the past, SiC epi-substrates had a small diameter, making mass production and cost difficult. Recently, however, it has become possible to use 8-inch substrates, and mass production and prices have been improving.

SiC is being actively used in relatively large power handling applications exceeding 10 kW, such as electric vehicle (EV) applications, power generation system applications, and residential power applications.

2. Differences Between SiC and GaN Devices

Along with SiC, gallium nitride (GaN) is another wide band gap semiconductor that is attracting attention. GaN has a larger band gap energy and higher dielectric breakdown strength than SiC, and is the subject of active research at research institutes.

Since GaN generally consists of a GaN active layer on a Si substrate, it is difficult to support high-power applications as well as SiC MOSFETs. In the market, applications that handle power equivalent to 1KW are relatively being considered. Examples include high power amplifier applications for 5G base stations and battery charging applications via PC or USB.

GaN devices, like silicon carbide (SiC) MOSFETs, can operate at high temperatures and do not require cooling equipment or excessive heat removal structures, which has led to their widespread use in recent years as compact PC power adapters.

What Is a Circuit Breaker Switch?

A circuit breaker switch is an electrical device that enables or disables the flow of power by opening or closing its contact points, functioning as a critical component in controlling and protecting electrical circuits. Commonly known as switches, these devices vary, with electromagnetic circuit breakers/contactors being standard in low-voltage scenarios. Thermal relays add functionality, differentiating electromagnetic switches from contactors.

Uses of Circuit Breaker Switches

Employed extensively in industrial settings, circuit breaker switches have diverse applications including:

• Driving motors for pumps and fans
• Controlling electric heaters
• Managing main power supplies for industrial equipment
• Powering commercial facilities with high-voltage

Protection against short circuits and overcurrent, especially in motor drives, is often managed with thermal relays and breakers to ensure safety and equipment integrity.

Principle of Circuit Breaker Switches

Electromagnetic contactors serve as a prime example, comprising terminals, contacts, an iron core with an electromagnetic coil, and a casing. Additional thermal relays define an electromagnetic switch, enhancing its functionality and application range.

1. Terminal

Connection points for wiring, which vary by region and application, ensuring secure electrical connections.

2. Contacts

The conductive parts that allow electricity to flow, designed to handle varying currents with materials like silver alloys for low resistance and gold for sensitive applications.

3. Iron Core and Electromagnetic Coil

These components magnetize when energized, driving the contacts to connect or disconnect the electrical circuit, with designs ensuring reliable operation through mechanical or magnetic latching.

4. Casing

Protects internal components while providing insulation, with modern designs allowing for easy mounting and robust protection.

Types of Circuit Breaker Switches

Circuit breaker switches come in various forms, including:

1. Electromagnetic Circuit Breaker Switch

Utilizes electromagnetic force for operation, suitable for low-voltage applications.

2. Push Button Station

A manually operated switch, holding its state until reset, used without thermal relays but crucial in direct control applications.

3. Airborne Category Switchgear

Designed for high-voltage circuits, these switches manage load disconnection and are often paired with protective devices to ensure comprehensive circuit protection.

What Is a Digital-To-Analog Converter?

A digital-to-analog converter is an electronic circuit that transforms digital signals into analog signals, bridging digital devices and the analog world. As digital devices like PCs and smartphones operate on digital signals, a digital-to-analog converter is essential when analog output, such as sound or light, is required. Due to the continuous nature of analog signals, the digital-to-analog converter output is an approximation of the digital input. An AD converter performs the inverse operation, converting analog signals to digital.

Uses of Digital-To-Analog Converters

Digital-to-analog converters are integral to devices requiring analog signal output, including PCs, smartphones, digital audio devices, and TVs. They also play a critical role in smart speakers with speech synthesis functions, converting digital audio data into analog signals. External digital-to-analog converters, offering high-quality audio output, have become popular for enhancing sound quality from digital sources. Moreover, digital-to-analog converters are used in video equipment for converting digital video data into analog signals for devices with VGA and RCA inputs. Industrial equipment also relies on digital-to-analog converters for precise, continuous control.

Principle of Digital-To-Analog Converters

The resistor-string method is a common, cost-effective digital-to-analog converter conversion technique, utilizing a series of resistors to create voltage levels proportional to the digital input. This method offers linear and accurate conversions but scales poorly with increased resolution. Alternative methods include capacitor-based, current source, and low-pass filter approaches for varying applications and performance needs.

Other Information on Digital-To-Analog Converters

1. Cautions When Using Digital-To-Analog Converters

Despite improvements in digital-to-analog converter conversion accuracy, the discrete nature of its output can introduce noise, affecting the analog signal quality. The performance of connected components, such as speakers, also influences the final analog output quality. Adjustments and component selections should be made with the system’s overall balance in mind.

2. Accuracy of Digital-To-Analog Converters

As digital-to-analog converters find applications in increasingly sophisticated systems, their precision becomes critical. Digital-to-analog converter accuracy is affected by offset error, gain error, and integral non-linearity error, with the total error being a combination of these factors. While offset and gain errors can be calibrated, integral non-linearity errors are more complex, necessitating memory for error parameters and careful management to minimize system load.