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What are Micro-Electromechanical Systems (MEMS)?

MEMS stands for Micro Electromechanical System. It refers to high-tech devices with a size of several millimeters or even smaller. Its internal structure is generally in the micrometer or even nanometer level. It is an independent intelligent system. It is mainly composed of three parts: sensors, actuators, and micro-energy. MEMS involves multiple disciplines and engineering technologies such as physics, semiconductors, optics, electronic engineering, chemistry, materials engineering, mechanical engineering, medicine, information engineering, and bioengineering. It has opened up broad applications in the fields of intelligent systems, consumer electronics, wearable devices, smart homes, synthetic biology of system biotechnology, and microfluidics. Common products include MEMS accelerometers, MEMS microphones, micromotors, micropumps, microvibrators, MEMS pressure sensors, MEMS gyroscopes, MEMS humidity sensors, etc. and their integrated products. Fundamental Principles and Structure of MEMS At the heart of MEMS lies the integration of micro-mechanical structures with sensors, actuators, electronic circuits, and control systems onto a small chip or substrate. These microstructures can include micro-mechanical systems such as micro-sensors (accelerometers, gyroscopes), micro-actuators (micro-valves, micro-pumps), micro-lenses, or micro-mirrors. Manufacturing MEMS devices typically involves processes akin to semiconductor fabrication, including photolithography, deposition, etching, and thin-film technologies, ensuring precise construction of micro-scale structures on silicon or other materials. Wide-ranging Applications MEMS technology has permeated numerous fields, playing pivotal roles in: Consumer Electronics: MEMS accelerometers and gyroscopes in smartphones, MEMS microphones and cameras in digital devices. Automotive Electronics: Accelerometers and inertial sensors in airbag systems, gyroscopes in vehicle stability control systems, MEMS inertial navigation modules in automotive navigation systems. Biomedical Applications: Biosensors, microfluidic control devices, drug delivery systems, and micro-bioreactors. Environmental Monitoring: Air quality sensors, micro-weather stations, and earthquake monitoring devices. Industrial Automation: Pressure sensors, flow meters, temperature sensors, and other industrial control and monitoring devices. Future Directions With advancing technology and increasing application demands, MEMS technology holds immense potential for future development. Future directions may include miniaturization, higher sensitivity, lower power consumption, increased functional integration, and cost-effective MEMS devices. Furthermore, the integration of MEMS with emerging technologies such as artificial intelligence and the Internet of Things (IoT) is expected to open new application scenarios and market opportunities. In summary, MEMS technology is not merely a niche technological field—it is a small yet powerful force driving modern technological advancement and innovation. It offers unprecedented convenience and possibilities for human life and industrial processes. As technology continues to progress, the application domains and influence of MEMS technology are poised to expand and deepen. For more information and updates, feel free to contact us anytime!our website:emi-ic.com

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What is a Rheostat?

A rheostat is a variable resistor which is used to control current. They are able to vary the resistance in a circuit without interruption. The construction is very similar to the construction of potentiometers. It uses only two connections, even when 3 terminals (as in a potentiometer) are present. The first connection is made to one end of the resistive element and the other connection to the wiper (sliding contact). In contrast to potentiometers, rheostats have to carry a significant current. Therefore ,they are primarily constructed as wirewound resistors. Resistive wire is wound around an insulating ceramic core and the wiper slides over the windings. Rheostats were often used as power control devices, for example to control light intensity (dimmer), speed of motors, heaters, and ovens. They are not typically used for this function anymore. This is because of their relatively low efficiency. In power control applications, they have been replaced by switching electronics. As a variable resistance, they are often used for tuning and calibration in circuits. In these cases they are adjusted only during fabrication or circuit tuning (preset resistor). In such cases trimpots are often used, wired as a rheostat. But dedicated 2-terminal preset resistors also exist. Types of Rheostats Several types of rheostats exist. The rotary type is the most commonly used in power control applications. Most of the time these rheostats use an open construction, but enclosed types are also available. Just as with potentiometers, multi-gang types are available. They are used to control multiple applications in parallel or to increase the power rating or adjustment range. Optionally, rheostats can be equipped with a mechanical stop to limit the minimum or maximum resistance. For special applications they can also be built with tapered windings. Slide rheostats are also available and often used for education and in laboratory environments. Linear or slide types are constructed of resistive wire wound on an insulating cylinder. A sliding contact is used to increase or decrease the resistance. Trimmers used as a variable resistance are very common on printed circuit boards. While dedicated preset resistors with 2 terminals exist, the 3-terminal trimmer potentiometer is more common and is often used by wiring it as a rheostat. How to Wire a Potentiometer as Rheostat? Any 3-terminal potentiometer can be wired as a rheostat by connecting to one end of the resistive track and to the wiper. It is best practice to connect the wiper together with the other end of the resistive track. Doing this prevents circuit interruption in case the wiper loses connection with the resistive track and also reduces noise during adjustment. Rheostat Symbols The following symbols are used according to the IEC standard. If you are interested in rheostat or any other electronic components, feel free to contact us!

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What is Microelectronics?

Microelectronics is a subfield of electronics that studies tiny complex machines or micro-chips that allow most of our devices to function, such as our cellphones. A microprocessor is a microchip. It is crucial in the field of microelectronics with billions of transistors per square centimeter, amplifying, controlling, and generating electrical signals. These transistors function as on and off switches that allow microelectronics to perform various Boolean operations by storing 1s and 0s. The Boolean operation or switching takes as little as 10 trillionths of a second. These transistors are tiny and unbelievably fast, allowing our modern devices to become smaller and faster in various applications. History of Origin Microelectronics has revolutionized the field of electronics and is rapidly transforming our lives and our world. The most fundamental building block of microelectronics, the transistor, was invented in 1947. John Bardeen Walter Brattain and William Shockley demonstrated the point-contact transistor to their co-workers at Bell Labs in New Jersey. The point-contact transistor is the first form of the transistor and was made from gold foil strips pressed into contact with a slab of Germanium on a plastic triangle. It is the size of a thumb which is much larger than the modern microscopic transistors. Bardeen, Brattain, and Shockley connected a microphone to one end of the unit and a loudspeaker on the other to test the amplification. The men took turns picking up the microphone and whispering, “Hello.” “HELLO!” yelled the loudspeaker on the other end of the line. This moment is significant to microelectronics because it is followed by a technological revolution throughout the world. The progress in microelectronics has been focused on shrinking the circuitry embedded onto chips. A decade later, Jack Kilby invented the integrated circuit (IC), a small circuit containing electronic components, including transistors, resistors,capacitors, and other components. Kilby worked for Texas Instruments, a semiconductor manufacturer, as an electrical engineer. Since each component had to be wired to any other component, he was irritated by the limited technical advancements. Because of the wires, the number of components used in devices was limited and sensitive to damage. Kilby constructed a circuit entirely out of semiconductors using Texas Instrument’s knowledge of silicon transistors and semiconductors. Kilby’s final product, the integrated circuit, eliminated the need to wire each part individually. It was much smaller than any other previously devised circuit. In 1965 Gordon Moore, one of the co-founders of Intel, published his observation regarding the future of microelectronics in the Electronics Magazine. Moore stated that the computing power of integrated circuits would increase exponentially along with the advancement of transistors over time, while the cost would decrease exponentially. The size of transistors shrank dramatically, and the number of transistors used in circuits grew rapidly. Moore’s observation drew a lot of attention and became known in the scientific world as Moore’s law. Moore’s law continues to be an accurate prediction of microelectronics’ future. Intel developed and introduced their first microprocessor, the 4004, chip in 1971. Intel designed the 4004 microprocessors with 2,300 transistors, which resulted in as much processing power as the room-filling ENIAC. Intel continually develops microprocessors with better processing powers that power most desktop computers to this day. The advancement of technology is at its peak, from phones to drones. Microelectronics plays a prominent role in humanity’s past and continuing progress in technology. Nanotechnology is expected to be the future of microelectronics, with far smaller components processing at much faster speeds. The Invention and Design of Semiconductor Components Semiconductor memories are information-storage microelectronic circuits. There are two types of memories: read/write and read-only memories (ROMs). Silicon and Germanium are metalloids, and their crystalline structure enables them to conduct electricity while still acting as insulators, thanks to their chemical elements. In addition, silicon is the most abundant element in the Earth’s crust. These materials and other passive components such as resistors, inductors, and capacitors are used to create microelectronic devices. A silicon chip will serve as the base to activate and deactivate the components in a controlled manner to send signals for a brief period. Despite its great usefulness, however, silicon cannot satisfy all demands of microelectronics. Microelectronics manufacturers are in search of a faster and more invincible material to integrate into circuits. Making any microelectronic system entails several measures. In this regard, integrated circuits are the most complicated. Circuit design and chip fabrication are the two parts of the process. When creating an integrated circuit, a complicated staging method is used to transmit a signal to the desired output 3. This necessitates reading a textbook, but an application on how the chip functions can be addressed. Application Example: RFID RFID stands for Radio Frequency Identification. It is a wireless technology that uses a chip electromagnetic frequency to identify something. RFID systems are used in most passports, vehicles, contactless card payments, smartphones, key fob, and more. An RFID system consists of a transponder (tag) and a reader. RFID readers are made up of a radio frequency module, a control unit, and an antenna that generated an electromagnetic field. On the other hand, a tag consists of a single antenna for receiving and transmitting signals and an integrated circuit (IC) that stores and processes data while controlling and decoding radio-frequency (RF) signals from the antenna. An interaction happens between a tag and a reader when they are close enough to share an electromagnetic field. This interaction ignites voltage in the tag’s antenna to power up the tag’s microchip. The microchip receives power and data of requests from the reader and returns the requested data to the reader. Since World War II, RFID technology has been a longstanding technology used to identify approaching friendly aircraft and enemy aircraft by the British military. The manufacturing of RFID chips has expanded in the last two decades. RFID technology has also enabled state-of-the-art techniques and advances in microelectronics health monitoring through contactless testing. Their use spread very quickly among many industries, from healthcare to ware stores. Career Goals to become an Electronic Design Engineer To pursue a career as an Electronics

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How Does the Resistor Color Code Work?

Resistor values are often indicated with color codes. Practically all leaded resistors with a power rating up to one watt are marked with color bands. The coding is defined in the international standard IEC60062. This standard describes the marking codes for resistors and capacitors. In addition to defining the color bands, the standard also includes numerical codes, as often used for surface mount SMD resistors. The color code is given by several bands. Together they specify the resistance value, the tolerance, and sometimes the reliability or failure rate. The number of bands varies from three to six. At a minimum, two bands indicate the resistance value and one band serves as multiplier. The resistance values are standardized; these values are called preferred values. Resistor Color Code Chart The chart below shows how to determine the resistance and tolerance for resistors. The table can also be used to specify the color of the bands when the values are known. An automatic resistor calculator can be used to quickly find the resistor values. Tips for Reading Resistor Codes In the sections below, examples are given for different numbers of color bands. But, first, here are some general tips for reading the color code: The reading direction might not always be clear. Sometimes the increased space between bands 3 and 4 provide an indication of the reading direction. Also, the first band is usually the closest to a lead. A gold or silver band (the tolerance) is always the last band. It is a good practice to check the manufacturer’s documentation to be sure about the color coding system used. When in doubt, measure the resistance with a ohmmeter. In some cases this might even be the only way to figure out the resistance; for example when the color bands are burnt off. 4 band resistor The four band color code is the most common variation. These resistors have two bands for the resistance value, one multiplier and one tolerance band. In the example shown here, the 4 bands are green, blue, red and gold. By using the color code chart, one finds that green stands for 5 and blue for 6. The third band is the multiplier, with red representing a multiplier value of 2 (102). Therefore, the value of this resistor is 56 · 102 = 56 · 100 = 5600 Ω. The gold band means that the resistor has a tolerance of 5%.  The resistance value lies therefore between 5320 and 5880 Ω (5560 ± 5%). If the tolerance band is left blank, the result is a 3 band resistor. This means that the resistance value remains the same, but the tolerance is 20%. 5 band resistor   Resistors with high precision have an extra band to indicate a third significant digit. Therefore, the first three bands indicate the significant digits, the fourth band is the multiplication factor, and the fifth band represents the tolerance. For the example shown here: brown (1), yellow (4), violet (7), black (x 100 = x1), green (0.5%) represents a 147 Ω resistor with a 0.5% tolerance. There are exceptions to this 5-band color system. For example, sometimes the extra band may indicate failure rate (military specification) or temperature coefficient (older or specialized resistors). Please read the subsection “Color Code Exceptions” below for more information. 6 band resistor Resistors with 6 bands are usually for high precision resistors that have an additional band to specify the temperature coefficient (ppm/˚C = ppm/K). The most common color for the sixth band is brown (100 ppm/˚C). This means that for a temperature change of 10 ˚C, the resistance value can change 1000 ppm = 0.1%. For the 6 band resistor example shown above: orange (3), red (2), brown (1), brown (x10), green (1%), red (50 ppm/°C) represents a 3.21 kΩ resistor with a 1% tolerance and a 50 ppm/°C temperature coefficient. Color Code Exceptions Reliability band Resistors that are produced according to military specifications, sometimes include an extra band to indicate reliability. This is specified in failure rate (%) per 1000 hours of service.  This is rarely used in commercial electronics. Most often the reliability band can be found on four band resistors. More information about the reliability can be found in the US military handbook MIL-HDBK-199. Single black band or zero-ohm resistor A resistor with a single black band is called a zero-ohm resistor. Principally it is used as a wire link that functions to connect traces on a printed circuit board (PCB). Using the resistor package allows the same automated pick-and-place machines to place the components on a circuit board. 5 band resistor with a 4th band of gold or silver Five band resistors with a fourth band of gold or silver form an exception and are used on specialized and older resistors. The first two bands represent the significant digits, the 3rd is the multiplication factor, the 4th is the tolerance, and the 5th is the temperature coefficient (ppm/˚C). Deviating colors For high voltage resistors, the colors gold and silver are often replaced with yellow and gray. This is to prevent having metal particles in the coating. If you are interested in resistors or any other electronic components, please feel free to contact us!  

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