Potentiometer is a kind of variable resistor, usually composed of a resistor and a rotating or sliding system, that is, by a moving contact to move on the resistor to obtain part of the voltage output.Classification of potentiometersAccording to the different materials required by its resistance body, potentiometers can be divided into carbon film potentiometers, metal film potentiometers, carbon solid potentiometers, organic solid potentiometers, wire-wound potentiometers, glass glaze potentiometers, etc.According to its structure, potentiometers can be divided into single-coil, multi-coil potentiometers, single-coupling, double-coupling coaxial potentiometers, with switching potentiometers, locking and non-locking potentiometers. According to the adjustment mode, it is divided into rotary potentiometer and straight sliding potentiometer.Parameters of potentiometerThe main parameters of potentiometer are nominal resistance, rated power, resolution, sliding noise, resistance change characteristics, wear resistance, zero resistance and temperature coefficient. In addition to the same parameters as the resistor, there are the following parameters.1. Variation of resistance valuePotentiometer is divided into linear potentiometer, exponential potentiometer and logarithmic potentiometer according to the law of resistance change with contact when adjusting.(1) The resistance value of the linear potentiometer changes linearly and uniformly with the movement of the sliding end. It is generally indicated by the character "X" and is suitable for the adjustment of partial pressure and bias flow.(2) The resistance value of the logarithmic potentiometer changes logarithmically with the movement of the sliding end. It is generally represented by the character "D" and is suitable for the tone control of radios, audio systems, etc.(3) The resistance value of the exponential potentiometer changes exponentially with the movement of the sliding end. It is generally represented by the character "Z" and is suitable for volume control of radios, stereos, etc.2. Dynamic noiseDue to the uneven distribution of resistance values and the existence of sliding contact resistance, the sliding arm of the potentiometer generates noise when the resistance body moves. This noise will have a bad effect on electronic equipment.Commonly used potentiometers are: WT series carbon film potentiometers, WH series synthetic film potentiometers, WS series organic solid core potentiometers, WTH-1, 2 series fine tuning glass glaze potentiometers, WH173 small straight slide carbon film resistors, WXD series wire wound potentiometers, etc.Measurement of potentiometer1. Potentiometer nominal resistance measurementThe potentiometer has three lead pieces: two end pieces and a center tap contact piece. When measuring the nominal resistance value, select the appropriate range of the multimeter ohm stop, put the two pens of the multimeter on the two ends of the potentiometer, and the resistance value indicated by the multimeter pointer is the nominal resistance value of the potentiometer.2. Performance measurementPerformance measurement mainly measures whether the center tap contact plate of the potentiometer is in good contact with the resistance body. When measuring, rotate the center contact piece of the potentiometer to any end of the potentiometer, select the appropriate range of the multimeter ohm stop, put a pen of the multimeter on any piece of the two ends of the potentiometer, and put another pen on the center tap contact piece of the potentiometer. At this point, the reading on the multimeter should be the nominal value of the potentiometer or 0. Then slowly rotate the potentiometer knob to the other end, the multimeter reading will continuously decrease from the nominal value or continuously rise from 0 as the potentiometer knob rotates until it drops to zero or rises to the nominal resistance value.In the process of rotating the potentiometer knob, the pointer of the multimeter should slide up or down smoothly, no jumping or jumping phenomenon, and the rotating inch potentiometer does not feel too loose or too tight.In the test potentiometer is good or bad, the main requirement is that the resistance value meets the requirements; Second, the contact between the central sliding end and the resistance body is good, and the rotation is smooth. For a potentiometer with a switch, the switch part should be accurate, reliable and flexible. Therefore, the potentiometer performance must be checked before use.

Encoders are devices that encode signals or data and convert them into signals that can be used for communication, transmission and storage. According to the imported encoder supplier brand awareness, quality level, after-sales service, innovation ability, consumer reputation and other indicators for comprehensive evaluation, released this list data, this list is only for the convenience of users to find a good encoder brand reference.HEIDENHAIN (Germany)HEIDENHAIN was founded in 1889 in Berlin, Germany, and in the early 1960s HEIDENHAIN turned to the production of linear grating rulers and Angle encoders for photoelectric scanning. The products of HEIDENHAIN guarantee the efficient operation of machine tools and large equipment. Since its reconstruction in Traunreut, Germany in 1948, HEIDENHAIN has delivered more than 7 million sets of linear grating ruler, 17 million sets of rotary encoders and Angle encoders, 500,000 digital display units and nearly 270,000 sets of TNC numerical control systems. HEIDENHAIN currently has offices in 49 countries and regions, the vast majority of which are wholly owned subsidiaries.Germany (P+F) Plus-plusPepperl + Fuchre (P+F) is a well-known sensor company in the global automation industry. Pepperl + Fuchs, as the global leader in the production of electronic sensors and components in the field of automation, has ensured its brilliant achievements for more than 60 years with continuous innovation, constant quality assurance and steady development. After nearly 60 years of continuous development and efforts, P+F has so far developed into more than 3,000 employees, from inductive sensors to ultrasonic sensors, from photoelectric sensors to rotary encoders, from identification systems to fieldbus systems, from liquid level, material level sensors to safety light curtains, From explosion-proof sensors to safety grids, isolation grids and other types of sensors have special research and products provided by global sensor suppliers.Union of Baumer (Switzerland)Baumer Electric Co., Ltd. is a world-renowned manufacturer of industrial automation sensor products with a history of 50 years, covering more than 110 countries around the world as a world leader in precision sensor technology, Baumer has been committed to the development of industrial automation and process control products. In the product accuracy, reliability, stability, diversity and effective demand to continuously meet customer requirements, to ensure that customers to provide products and perfect after-sales service and product upgrade services. If you need to regulate, control and monitor the process of rotation or linear motion to determine the angular position of the motor and spindle, the direction of rotation and the number of revolutions, then Baumer is one of your suppliers. Whether it's micro-rotary encoders, high-resolution encoders or encoders with heavy-duty housings, whether it's counters or spindle positioning systems, we have the right product for you.Germany (TR-Electronic) TeerTr-electronics GMBH is a German company that manufactures and sells encoders and automation systems for industrial computers. Main research and development and production of Angle and linear displacement measurement systems, including incremental rotary encoders, absolute. Alignment rotary encoder, magnetostrictive linear displacement sensor, grating ruler, laser rangefinder and intelligent positioning driver, etc. One of the best. Multi-turn rotary encoder with high resolution up to 36 bits. Whether in China and Germany or in the world's heavy industry, chemical industry, machinery manufacturing and other manufacturing fields, TR-Electronic products have won high praise from customers in terms of high precision, reliability and durability, is the industry leader.HENGSTLER, GermanyHenschler was founded in 1846, and after decades of development, the company has introduced various products, such as: counters, printers, cutters, relays and rotary encoders. These products have gradually become the pillar industry of Henschler Company today. We also offer linear and angular measurement systems. In 1995, Henschler officially became a member of Danaher Group. Henschler is a leading European manufacturer of industrial components with a product line covering counters/timers, rotary encoders, industrial-grade temperature controllers, relays, printers and cutters. Thanks to our extensive application experience and customer service, we have a large number of industry application experience and flexible product prices like our products serve all walks of life. Not only that, we can also help customers effectively tailor products to meet the needs of the project.The Japanese OMRONFounded in 1933, Omron Group is a world-renowned manufacturer of automatic control and electronic equipment, mastering the world's advanced sensing and control core technology. By constantly creating new social needs, the Omron Group has grown to more than 36,000 employees worldwide and a turnover of 773 billion yen. Products involve industrial automation control systems, electronic components, automotive electronics, social systems, health and medical equipment and other broad fields, varieties up to hundreds of thousands.Germany (SIKO)SIKO Measurement and Control Co., Ltd. has been engaged in the development and manufacturing of non-contact magnetic gate measurement and control products in Germany since 1963, and has established more than 30 branches all over the world. Over the years, SIKO has used advanced mechanical and electronic technology. We have developed, designed and manufactured a large number of mechanical, electronic and photoelectric measuring, display and control instruments and equipment for measuring position and Angle. Precision - quality is the consistent purpose of German SIKO company. German SIKO company according to the specific requirements of different users in the world, invented and created a variety of different products. SIKO's products provide products for the needs of various industries and markets.American (AMCI) AmercoAMCIAdvancedMicroControlsInc company mainly produces stepper motor control, PLC modules, rotary sensors, industrial control network devices, single StandAlone solutions, packaging systems and control, and stamping technology products such as the eight plates, AMCI has greater influence in the global market, Mainly used in factory automatic control, packaging system control and stamping control fields. AMCI's DURACODER encoders are designed for the world's harshest conditions and are the industry's most cost-effective products in the 2.5 "(63.5mm) specification, including incremental, unique. Dual (digital, voltage or current analog, DEVICENET), mainly used for motor speed feedback, material cutting positioning, CNC machine tools, packaging machinery, material handling, pharmaceutical, metal processing, food processing and mobile brackets.Esme, Germany (ASM)ASM is the world's leading encoder manufacturer. The main products are: ASM displacement sensor, pull rope displacement sensor, pull rope encoder, displacement sensor, pull rope sensor, pull rope encoder, encoder, incremental encoder, absolute. Pair encoders, etc. Headquartered in Munich, Germany, ASM has been at the forefront of displacement sensing technology with its thirty years of experience in the production of displacement sensors. German ASM products can provide high product quality and measurement accuracy, and in the ASM laboratory continuous research and development work and quality management, so that ASM displacement sensor has been the consistent characteristics of high quality and precision has been guaranteed. Sensors are the basis of automation control in modern industry, and high-quality, high-performance and highly homogeneous products are the key to ensure the effective and stable operation of automation control systems. Displacement sensors manufactured by ASM are widely used in measurements requiring automatic control, detection, and monitoring of distance, position, or length.South Korea (AUTONICS) AutonicsAutonics is a factory automation sensor and controller company. All products of Autonics have obtained several major world certification specifications and are sold all over the world at a wide range of reasonable prices. Its products are favored by users with low price and reliable quality, and are widely used in all walks of life.

First, the working principle of switching power supplyAs the name suggests, switching power supply is the use of electronic switching devices (such as transistors, field effect transistors, thyristors, etc.), through the control circuit, so that the electronic switching devices constantly "on" and "off", so that the electronic switching devices pulse modulation of the input voltage, so as to achieve DC/AC, DC/DC voltage conversion, and the output voltage can be adjusted automatically.Switching power supply is generally composed of pulse width modulation (PWM) control IC and MOSFET. Compared with the switching power supply and the linear power supply, the cost of both increases with the increase of the output power, but the growth rate of both is different. The cost of linear power supply is higher than that of switching power supply at a certain output power point, which is called the cost reversal point. With the development and innovation of power electronics technology, switching power supply technology is also constantly innovating, and this cost reversal point is increasingly moving to the low output power end, which provides a broad space for the development of switching power supply.Second, the working principle of switching power supply - structureSwitching power supply is roughly composed of the main circuit, switching power supply control circuit, detection circuit, auxiliary power supply four major parts.1. Main circuitImpulse current limiting: Limits the impulse current of the instant input side of the power supply.Input filter: Its role is to filter the clutter existing in the power grid to prevent the clutter generated by the machine to feed back to the power grid.Rectifier and filter: the AC power supply of the grid is directly rectified into a smoother direct current.Inverter: The rectified direct current into high-frequency alternating current, which is the core part of the high-frequency switching power supply.Output rectification and filtering: Provide stable and reliable DC power supply according to load requirements.2. Control circuitOn the one hand, sample from the output, compare with the set value, and then control the inverter, change its pulse width or pulse frequency, so that the output is stable, on the other hand, according to the data provided by the test circuit, identified by the protection circuit, provide a control circuit to the power supply for various protection measures.3. Detection circuitProvide protection circuit in the operation of various parameters and various instrument data.4. Auxiliary power supplyRealize the software (remote) start of the power supply, and supply power for the protection circuit and control circuit (PWM and other chips).