The Kynix Blog

Summary Last days,I bought a new house and I am considering how to decorate it. when thinking about wall-lighting sconces.My project is to place an array of LED strips on the walls,covered with translucent(or in some cases,opaque!) Yeah,Plexiglas plates mounted a few centimetres away. That's the plan anyway...   Preparation At first, I need a 18W power supplies small enough to fit into an electrical box.Finally,I chose a power supply.This product could provide a full 1.5A without collapsing.However,upon opening the cases,the component temperatures after rumming at full-throttle for a new minutes suggested otherwise.The switching transistor,output rectifier,and output capacitor were all far too hot for comfort.I imagine the 18W spec is only valid for one day of use. Figure 1  The 12V 18W PSU. Notice the 100% efficiency (IN & OUT are both 18W), and  the dire warning not to touch the surface of the plastic case because of high temperature   I also bought one PSU from Aliexpress.They behave differently than the first batch. From an external vantage point, they’ll only supply 1.3A as opposed to the former 1.5A. The output voltage collapses to 8V at 1.5A.Take it apart, and further differences appear. Most noticeably, the 12V output capacitor does not egregiously overheat at, say, 1.3A. Sure enough, the part has “Low ESR” printed on the case. The previous caps don’t. Figure 2  PSUs from AliExpress (top) and another, forgotten source (bottom). Note the  convenient dates at the bottom of the boards. Manufacture has transitioned from phenolic to fiberglass   The design appears to be a simple self-oscillating circuit. I measured the switching frequency to be about 100 kHz. The 12V output caps are at the upper-right of each board. Though the legend says “1000µF 25V”, the installed caps are 470µF.   After discovering the output cap heat problem (but before getting the second PSU batch), I sourced a bagful of quality capacitors – 270µF @ 35V, still more than enough capacitance for this circuit, but with a high ripple-current rating and low ESR. Both of the boards above have these new parts installed. They run cool as a cucumber, versus the slight temperature rise of the second PSU caps, and of course, the extreme rise of the first ones. Figure 3  The PCB bottoms reveal other minor design changes in the newer boards – mainly exposed copper to pick up current-fortifying solder   I’m constantly struck by the strange state of affairs at this level of Chinese manufacture. Clearly, there is some thought and skill put into design and production, yet we still end up with stupidities, like unsuitable parts, or wishful-thinking specs. As I mentioned, other parts get hot too. The switching transistor can get toasty at higher loads, but it was the output rectifier I focused my measurements on. At 1.33A, free-air TC registered 90°C. At 1.2A, 86°C. Figure 4  My test setup here at EDN Labs. Note the many safety protocols employed on the bench   Enclosed in its case, in an electrical box, I don’t think I’ll want to pull more than 1.1A from these PSUs. Hopefully, that will be enough for my LED lighting. Other options: Squeeze two PSUs into a box (possibly swapping the case for some shrink wrap or electrical tape), or, cut a hole in the case so I can bend the rectifier out and heat-sink it to the electrical box! Hmm. We’ll see.   Result I didn't realize my plan until now.I am so tangle should choose which one? The last one,there is an absence of an AC line filter on the board.The former, at least, has a line filter, and even if they also don’t meet their output-current spec, they will certainly be better than the PSUs I’m using. But…they don’t fit into an electrical box.How do you think about my plan? Anyaway,I will attempt it again when I am free.  

NewsKynix will attend the 49th Korea Electronics Show (KES) 2018 from 24,October to 27, October 2018 in Korea; hours: 10 a.m.- 5 p.m. on Oct. 24 to 26 / 10 a.m.- 4 p.m. on Oct. 27. Our Booth Number in Korea Electronics Show is E320. we sincerely invites you to visit this exhibition.It is believed that you can have a better understanding of our company and we can form a stable partnership. Following are some information about the Korea Electronics Show. About Korea Electronics ShowThe Korea Electronics Show (KES) is a professional electronic Show certified by the international UFI. It is well known in the Asia-pacific region. It is one of the exhibitions of the Asia electronic Show alliance (AEECC).For a long time, Korea electronics show has become a bridge for cooperation between Chinese and Korean enterprises. Chinese electronics and household appliances enterprises have also gained the opportunity to exchange and cooperate with excellent Korean enterprises in the exhibition, and have rapidly opened up the Korean and overseas markets, thus enabling China to launch a step.Believe that there will be greater harvest!   Times The 49th Korea Electronics Show (KES) takes place on 4 days from 24,October to 27, October 2018 in Korea.Hours: 10 a.m.- 5 p.m. on Oct. 24 to 26 / 10 a.m.- 4 p.m. on Oct. 27   Themes of the exhibitionConvergence and Innovation Open up the Future Events in Number Exhibiting Companies:500Attendees:60000Exhibition Area:13500sqmFrequency:Annually Well-known Exhibitors Profile Booth Number                                                                                    Company Name                                                                            E320                                 Kynix                              C262                                 Avnet                               E518                                 cvilux                              C480                                                                                         Daimler AG                                                                       A221                                                                                          Gve                              S113                                                                                                      Luxy Star Electronics Inc.                                                            E520                                                                                           Chip One Stop, Inc.                                                            S114                                                                                            RITDISPLAY                           D192                                                                                                      Inlife-Handnet Co., Ltd.                                                    S110                                                                                                       LENOO ELECTRONICS CO., LTD                                              A148                                  OUTTOS INDUSTRIAL CO ., LTD                                        A147                                                                                           FRONTIER CIRCUIT LTD                                                      Exhibitor Profile Home entertainment                                                          automotive electronics products                                                              digital television                  Automobile navigation system                    LCD/PDP TV                       on-board computer                                                                        DVD                            intelligent transportation system (ITS) terminal        AddressCoex, 513, Yeongdong-daero, Gangnam-gu, Seoul, Korea, 06164Korea Electronics Show is one of the largest and modern fairgrounds of the world, a full member of The Global Association of the Exhibition Industry UFI in categories of Exhibition Organizers and Exhibition Centres.Coex official caterer is Gramercy Banquet & Conventions providing delicious options for your event. From small to large-scale events, Gramercy offers delicious fare and differentiated services to meet the need of your event and participants. This includes breakfasts, brunches, lunches, cocktail parties, dinners, banquets, themed parties, and special events.  About kynixKynix Semiconductor has founded over 10 years since 2008. These 10 years have witnessed our company's trials of becoming a better and better distributor and supplier in electronic components industry.In 2009, our company established the International Sales Department and became members of TBF and HKInventory. In 2010, we established cooperative relationships with accredited testing organizations like CECCLab, White Horse Lab, AAA...In 2013, we established a strategic partnership with dozens of well-known electronic components manufacturers including TI.In 2015,we reached an electronic components supply strategic partnership with Foxconn. Also ,our B2B trading platform was launched officially,whose members have exceeded 15,000 in 2017. Our partners in electronics field have increased to 700 up to now.In 2017, We attended Korea Electronic Show(KES), we won a lot of new partners and opened up kynix’s world market.  Our advantages         1. Strong operation system2. Good warehouse management3. Cooperation with advanced international testing companies4. Cooperation with international high standard logistics companies like UPS, DHL, TNT, FedEx5. Competitive supply from SumSung / Micron / BroadCom / Freescale / Atmel / Cypress and etc...6.After-sales Services7.Gurantee8.Commitment to Quality  Kynix attened the 2018 EXPO ELECTRONICAExpo Electronica in Moscow is an international exhibition of electronic components, modules and systems. The show is constantly growing and every year attracts more exhibitors and visitors from Russia, the CIS and other foreign countries.  ContactIf you have any questions, please contact us through the following contact information! Hope the exhibition finishes perfectly! We will be there and waiting for your coming! Telephone： +86-0755-88605655Fax：           0755-88603420Email：       info@kynix.com

Regarding the design of a micropower isolated power supply for the two-wire transmitter, we must know what is the transmitter first. When the output of the sensor is a specified standard signal, it is called a transmitter. A sensor, usually composed of sensitive elements and conversion elements, is a floorboard for a component or device that can be measured and converted into a usable output signal according to certain rules. And the common types are power transmitters, current-voltage transmitters, and so on.How to Build a FM Radio Transmitter CatalogI. Brief Introduction to Internal Micro-power Supply DesignII. Overall DesignIII. Constant Current Voltage Stabilizing CircuitIV. DC/CD in CircuitV. Isolated Power Source WindingVI. ConclusionFAQ I. Brief Introduction to Internal Micro-power Supply Design The design of an internal micro-power supply is very important when developing a low-power intelligent two-wire transmitter. Firstly, in order to satisfy the power supply of the micro-controller, A/D, D/A, and communication circuit, the intelligent transmitter with microprocessor needs more power than that of an ordinary 4~20mA one), and its power supply efficiency of the internal power supply must be higher.  In addition, for capacitive sensors and thermocouples, it is necessary to consider the case of grounding or the possibility of the sensor earthing. So the input and output of the designed transmitter circuit must be isolated, only this way can guarantee the normal operation of the follow-up control system and the ability of anti-common-mode interference.  Since the external circuit provides the maximum working current of 4mA for the two-wire transmitter system, specific requirements like this bring great difficulties and challenges to the design of the power supply of the system. Adopting a full integrated circuit, the isolated two-wire transmitter power supply with micro-input power has the advantages of simple structure, stable performance, and low cost. And it takes the 12~35V DC as the input power, designing the simple input circuit of the constant current and stable voltage front end, fixing the consumption of 315mA current, and providing two sets of isolated 3V power supply. In this case, the not isolated imputing group with maximum 5mA load capacity and the isolated imputing group with maximum 3mA load capacity, which can meet the requirements of input and output isolating two-wire transmitters for power supply.  II. Overall Design Fig.1 is a schematic diagram of the power supply. It consists of three main parts: 315mA/812V constant current voltage stabilizing circuit composed of U1, R1, and Z1; DC/DC converter circuit composed of U2 as the core; and a set of isolated power supply composed of L2 and U3. The system is designed to be concise and highly integrated, and all selected components can work at -40 ~ 85 ℃, which can ensure the reliable application of the power supply to field transmitters.Fig.1 Schematic Diagram of Power Supply III. Constant Current Voltage Stabilizing Circuit As a power supply to the two-wire transmitter, the maximum working current is 4mA. The transmitter with this power supply needs some low zero output indication, so the general system power supply standard is usually below 315mA, meanwhile, this type of power supply must have constant current characteristics to meet the operating requirements of the two-wire transmitter. And there are many ways to design constant-current sources. The design in Fig.2 adopts the three-terminal adjustable voltage stabilizer LM317L to design a constant-current source. LM317L is a three-terminal adjustable voltage stabilizer, and its application is as follows in Fig.2. Its basic application as a standard regulator is shown in Fig.2 (a), where a steady pressure difference is generated between the output and adjustment terminal, the typical value is 1125V, so its output voltage is VO=1125 (1+Ra/Rb). Because of the stable pressure difference of LM317, it is often used to design the constant-current source. Fig.2 (b) is a typical application circuit, which generates a current of I=1125 / R, consulting Fig.1; the R1 value in the design is 360Ω, so you can obtain a constant current of about 315mA.  Considering the working voltage range of the subsequent DC/DC chip is 4~11V and the actual out the power supply, a voltage stabilizer Z1 with 812V is used to parallel the voltage stabilizing function while providing a stable inlet voltage for U2. It requires that the U2 total current consumption is less than 314mA and Z1 must be the high-quality voltage stabilizer with the breakdown current less than 011mA (Philips products can be used, the lowest static stable current is only dozens of μA). Fig.2 Typical Application of LM317LThe D1 of the front end of the circuit is an anti-inversion diode( as shown in Fig.1), generally using 1N4148. The fuse is the PTC device self-recovery fuse, its parameter is 100mA/ 60V, which ensures that the external power supply will not be affected when the power supply fails. The field transmitter is the final application of the power supply. Its changing ambient temperature is in a wide range, so the temperature drift must be taken into account. The main temperature drift of the power supply is the constant current drift, which is caused by the temperature drift of the reference voltage difference of LM317L and the temperature drift of the constant current resistance R1. In reality, the temperature drift can be neglected when the temperature coefficient is below 5*10-6/℃.  The relationship between the reference pressure difference and temperature coefficient of LM317L is shown in Fig.3: The temperature effect is obvious in the temperature range of - 40-85%, thus compensation must be made in the high precision application. In intelligent transmitter systems, in order to correct sensors and compensate circuits, temperature sensors are commonly designed in the transmitter circuits, because the practical applications of power supply are aimed at intelligent transmitters. But the digital thermometric chip, like LM75 or TC77, does not design a special hardware compensation, while a software compensation algorithm provided when applying power supply to deal with temperature drift.  Fig.3 LM317L Benchmark Temperature CurveAs shown in Fig.3, the curve of the relationship between the reference pressure difference and temperature of LM317L is approximate to a simple cubic polynomial function. It only needs to design a compensation function for the reverse Y-axis, and the system is calibrated at 20 ℃ as the basic compensation. The specific compensation formula is ΔI=A (t-20)2+B (t-20) in which “t” is the ambient temperature. The coefficients A and B can be derived from the reference voltage temperature curve provided by the LM317L chip manual, the simplest method is to obtain two binary linear equation groups for solving A and B by taking two points of -20 ℃ and 60 ℃. In this way, it is easy to obtain an approximate function of the compensation curve with a good fitting degree, and the effect of compensated temperature drift can be neglected basically. The biggest difficulty of power supply design is that the input power is very small, thus the isolated feedback mode with high power consumption should be avoided in the design of the isolation terminal, and the open-loop auxiliary side should be used in the actual circuit. The specific process is using MAX639 to design the core circuit of DC/DC, which realizes the high power efficiency conversion. For example, when the input of 315mA is supplied, it can supply the circuit with a current much larger than that of 315mA, thus solving the need for a large current in an intelligent system. According to the requirements of the system, the core chip must have the advantages of low power consumption, high efficiency, wide input voltage range, and simple peripheral devices. The DC/DC chip in Fig.1 is MAXIM's MAX639, which is a step-down converter chip. Its main features are wide input voltage range (4~115V), high conversion efficiency (up to 90%) and low static current (10 μ A); fixed output or an adjustable output. IV. DC/CD in Circuit The circuit is designed for adjustable output and the output is set to 3V. Output current: Io=（Vi Ii η）/Vo, Vi is the input voltage; Ii is the input current, and η is the conversion efficiency and Vo is the output voltage. In the circuit, Vi=812V, Ii=315mA,η= 90%, Vo=3V, getting an approximation Io=816mA without considering the isolating side output, this output current is already a relatively large supply capacity in the low-power system. But the calculation of the above Io is only theoretical, if you want to make the circuit operate reliably under the condition of micro-input power such as 315mA/812V, and to obtain more than 90% conversion efficiency, it is necessary to design the circuit very carefully. The reliable operation of DC/DC is restricted by many conditions, the necessary condition is providing sufficient start-up pulse current. A 10μF tantalum electrolytic capacitor C2 in parallel to Z1 provides an operation guarantee, also it can effectively avoid the interference of DC/DC work on the constant current of LM317. The inductance L1 plays a decisive role in the conversion efficiency of DC/DC. The algorithm provided by the MAXIM manual is L1=50/I0, μH is the unit of L1 and A is the unit of I0. In the practical circuit, the value of L1 is 4mH, which can ensure the circuit work stably under the maximum output power, and it can keep the high conversion efficiency at the same time. what should be emphasized is that if L1 is small, the conversion efficiency of the circuit will be reduced, the starting current will increase and even can not operate. If L1 is larger, the output capacity will decrease and the DC/DC circuit will oscillate. To ensure the stability of the circuit, DC / DC chip has a high requirement for output capacitor C3, the most important is that its equivalent series resistance ESR must be smaller, and it must have enough capacity at the same time. So a 10μF tantalum electrolytic capacitor with excellent performance is used in the circuit design, which can guarantee a stable output. The DC/DC chip is the core of the circuit, and the actual circuit layout has a great influence on the performance of the circuit, especially on the output ripple. The unreasonable layout design of the circuit board will even bring extra parasitic oscillation in the output, so much more attention should be paid to the design. Thus the most important principle is that the ends of C2 and LI lead should be as close as possible to the MAX639 pin, and the grounding pins of C2, D2, MAX639, R3, and C3 should be as close as possible to each other, linking with thick wires. The setting input voltage of DC/DC is 812V, which is guaranteed by Z1. If the actual transmitter requires a lower power supply, Z1 can choose a lower stable voltage, which makes the whole power supply require a lower input voltage. The low threshold of the inlet voltage is 12V; if Z1 selects 612V, the threshold voltage can be reduced to 10V. V. Isolated Power Source Winding The main feature of the circuit is to provide an isolated power supply winding, which uses the method of "stealing" electricity on the DC/DC output energy storage inductor. In Fig.1, the L2 is the power supply coil for this isolated power supply. Because the isolating power supply is a secondary coil loaded on the energy storage coil of DC/DC, and its structure is an open loop, therefore its output stability is relatively poor. In order to obtain satisfactory results, it is necessary to consider the whole design from different angles.First of all: determine its output power. Because of the method of "stealing" electricity from the energy storage coil, its output power is limited and can only be smaller than the original side output power. The output of this set of isolated power supply is mainly supplied by sensor conversion circuit, front-end A/D converter, and isolated circuit in the application of specific transmitters. And the power consumption of analog measuring circuits of differential capacitance sensors, thermocouple sensors, and thermal resistance sensors reaches μA level. The front-end A/D is usually multi-integral or Σ-Δ, the power consumption is less than 1 mA, and the whole low power dissipation optoelectronic isolation can be below 1mA. Therefore, isolated windings provide 3mA that can meet the actual needs. It has been calculated that the maximum output of the circuit is 816mA without the secondary winding, so it is obvious that the 3mA current can be supplied in the case of the secondary winding. Secondly: Avoid working / hibernating rotation for devices with high power consumption. The isolation winding adopts an open-loop structure, and the change of load on the primary side directly affects the stability of the secondary side, so it is required that the power consumption stability of the original circuit system should be guaranteed as much as possible when the circuit is used in practice. What’s more, the circuit can provide the maximum 5mA current for the original edge and can fully meet the requirements of the commonly used low-power MCU control system without the use of sleep mode. In this way, the maximum system running speed can be obtained. Finally:  the low-voltage difference linear regulator and the DC/DC converter should be used in the design. The isolated power winding mainly supplies power to the front-end small-signal analog circuit, therefore, the quality of the power supply requires high. Noise reduction and voltage stabilization treatment of low voltage output converted by DC/DC through low dropout linear regulator(LDO), which can not only improve the efficiency of power supply but also meet the requirement of small ripple voltage. Specifically, LDO uses MAX1726 chip, its working current is the only 2μA, the output is 313V; The output amplitude before voltage stabilization depends on the output power of the original edge and the inductance of L2, the experiment confirmed that L2 is 3mH. When the primary current varies between 3~5mA and the secondary current is 2mA, the voltage fluctuates between 318V and 418V before the voltage stabilizes, which meets the input requirements of the LDO voltage stabilizer. VI. Conclusion The isolated power supply of two-wire transmitter is stable and reliable, and can meet various complex requirements of the use of two-wire transmitter. It has the characteristics of wide temperature range, wide input voltage range, high output efficiency, high integration, good isolation performance, small volume and low cost. And this power supply has been applied to the integrated intelligent temperature transmitter, after a long period of field test, finding that it has excellent performance and can fulfill the requirements of the isolated two-wire transmitter completely. FAQ 1. What does a transmitter do?In the Telecommunications world, a Transmitter is a device that produces radio waves radiating from an antenna. In the world of process control, a Transmitter is a device that converts the signal produced by a sensor into a standard instrumentation signal representing a process variable being measured and controlled. 2. What is called transmitter?In electronics and telecommunications a transmitter or radio transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. 3. What is transmitter and its types?Pressure transmitters are divided into three types: Absolute Transmitter: This transmitter take vacuum pressure as its base, and then measures process pressure. Gauge Transmitter: This type measures process pressure with the location's atmospheric pressure as a base. 4. What are the main features of transmitter?Some of the main features which make the transmitter complex are higher clock speed, higher transmit power, directional antennas and need for a linear amplifier. 5. What is transmitter frequency?A radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. Radio waves are electromagnetic waves with frequencies between about 30 Hz and 300 GHz. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. 6. What is the difference between transmitter and antenna?A transmitter is a different kind of antenna that does the opposite job to a receiver: it turns electrical signals into radio waves so they can travel sometimes thousands of kilometers around the Earth or even into space and back. Antennas and transmitters are the key to virtually all forms of modern telecommunication. 7. What is difference between transmitter and transducer? Transducers and transmitters are virtually the same thing, the main difference being the kind of electrical signal each sends. A transducer sends a signal in volts (V) or millivolt (mV) and a transmitter sends a signal in milliamps (mA). 8. What is transmitter PLC?Transmitters are also referred to as stationary instruments and convert measurement parameters into an electrical signal that is then sent to a BMS ( Building Management System), PLC ( Programmable Logic Controller), SCADA ( Supervisory Control and Data Acquisition). 9. What is the pressure transmitter?A Pressure Transmitter is an instrument connected to a Pressure Transducer. The output of a Pressure Transmitter is an analog electrical voltage or a current signal representing 0 to 100% of the pressure range sensed by the transducer. 10. Which oscillator is used in transmitter?Crystal oscillators are the most common type of linear oscillator, used to stabilize the frequency of most radio transmitters, and to generate the clock signal in computers and quartz clocks. You May Also LikeThe 3W PowerSpot transmitter for Power Over-the-air from PowercastBuild a Remote RC Firecracker and Firework lgniter Using RF Transmitter4 Channel 2 Core Twisted Pair Remote Controller Using PT2262

This article introduces stepper motor at full length.There are five parts of this article--the definition of stepper motor; types of steppers; how a stepper motor work; how to select and the basic wiring.  CatalogI. What is a Stepper Motor?II. Types of Stepper MotorsIII. How Does a Stepper Motor WorkIV. How to Select a Stepper motorV. Basic Wiring of Stepper MotorFAQI. What is a Stepper Motor? A Stepper Motor or a step motor is a brushless, synchronous motor which divides a full rotation into a number of steps. Unlike a brushless DC motor which rotates continuously when a fixed DC voltage is applied to it, a step motor rotates in discrete step angles. The Stepper Motors therefore are manufactured with steps per revolution of 12, 24, 72, 144, 180, and 200, resulting in stepping angles of 30, 15, 5, 2.5, 2, and 1.8 degrees per step. The stepper motor can be controlled with or without feedback.   II. Types of Stepper MotorThere are a wide variety of stepper types, some of which require very specialized drivers. By construction the step motors come into three broad classes: 1.Permanent Magnet StepperPermanent magnet motors tend to "cog" as you twist the rotor with your fingers, while variable reluctance motors almost spin freely (although they may cog slightly because of residual magnetization in the rotor). You can also distinguish between the two varieties with an ohmmeter. Variable reluctance motors usually have three (sometimes four) windings, with a common return, while permanent magnet motors usually have two independent windings, with or without center taps. Center-tapped windings are used in unipolar permanent magnet motors. 2.Variable Reluctance StepperJust as resistance determines the flow of electric current, reluctance determines the flow of magnetic flux. In a variable reluctance (VR) stepper, the rotor turns at a specific angle to minimize the reluctance between opposite windings in the stator. The primary advantage of VR steppers is that they have an excellent angular resolution. The primary disadvantage is low torque. 3. Hybrid Step MotorHybrid stepper motors provide excellent performance in areas of torque, speed, and step resolution. This type of motor provides a combination of the best features available on both the PM and VR types of stepper motors. Permanent magnet and hybrid stepper motors are two types of the most commonly used stepper motors. Permanent magnet and hybrid stepper motors are two types of the most commonly used stepper motors. III. How Does a Stepper Motor Work Stepper motors consist of a permanent magnetic rotating shaft, called the rotor, and electromagnets on the stationary portion that surrounds the motor called the stator. Figure above illustrates one complete rotation of a stepper motor. At position 1, we can see that the rotor is beginning at the upper electromagnet, which is currently active (has voltage applied to it). To move the rotor clockwise (CW), the upper electromagnet is deactivated and the right electromagnet is activated, causing the rotor to move 90 degrees CW, aligning itself with the active magnet. This process is repeated in the same manner at the south and west electromagnets until we once again reach the starting position.  In the above example, we used a motor with a resolution of 90 degrees for demonstration purposes. In reality, this would not be a very practical motor for most applications. The average stepper motor's resolution -- the number of degrees rotated per pulse -- is much higher than this. For example, a motor with a resolution of 5 degrees would move its rotor 5 degrees per step, thereby requiring 72 pulses (steps) to complete a full 360-degree rotation. You may double the resolution of some motors by a process known as "half-stepping". Instead of switching the next electromagnet in the rotation on one at a time, with half-stepping you turn on both electromagnets, causing an equal attraction between, thereby doubling the resolution. As you can see in Figure 2, in the first position only the upper electromagnet is active, and the rotor is drawn completely to it. In position 2, both the top and right electromagnets are active, causing the rotor to position itself between the two active poles. Finally, in position 3, the top magnet is deactivated and the rotor is drawn all the way right. This process can then be repeated for the entire rotation.  IV. How to Select a Stepper Motor Selecting between a servo motor and a stepper motor can be quite a challenge involving the balancing of several design factors. Cost considerations, torque, speed, acceleration, and drive circuitry all play a role in selecting the best motor for your application.  At first, we need to know the basic differences between stepper and servo motors.   Stepper and servo motors differ in two key ways, in their basic construction and how they are controlled.  Stepper motors have a large number of poles, magnetic pairs of north and south poles generated either by a permanent magnet or an electric current, typically 50 to 100 poles. In comparison, servo motors have very few poles, often 4 to 12 in total. Each pole offers a natural stopping point for the motor shaft.  Driving a stepper motor to a precise position is much simpler than driving a servo motor. With a stepper motor, a single drive pulse will move the motor shaft one step, from one pole to the next. Since the step size of a given motor is fixed at a certain amount of rotation, moving to a precise position is simply a matter of sending the right number of pulses. In contrast servo motors read the difference between the current encoder position and the position they were commanded to and just the current required to move to the correct position.The greater number of poles allows a stepper motor to move accurately and precisely between each pole and allows a stepper to be operated without any position feedback for many applications. Servo motors often require a position encoder to keep track of the position of the motor shaft, especially if precise movements are required. Note that with today's digital electronics, stepper motors are much easier to control than servo motors. All in all, Selecting the best motor for your application depends on a few key design criteria for your system including cost, positional accuracy requirements, torque requirements, drive power availability, and acceleration requirements. Overall, servo motors are best for high speed, high torque applications while stepper motors are better suited for lower acceleration, high holding torque applications. V. Basic Wiring of Stepper Motor  Stepper motors are available in two basic wiring configurations, bipolar and unipolar. Unipolar motors have one winding with a center tap for each phase. This allows the motor direction to be reversed easily by changing which section of the phase is powered rather than reversing the flow of current. This allows the control circuitry to be very simple. Unipolar motors typically have six leads, three for each phase, but can also be found with five leads, with the center tap of both phases internally connected. Unipolar motors can be easily controlled with a microcontroller or stepper motor controller and are very affordable.  Bipolar motors have one or two windings without a center tap for each phase. In order for the direction of rotation to be reversed on a bipolar motor, the current direction needs to be reversed. This requirement makes the driving circuitry more complicated and is generally implemented with an H-bridge control arrangement or an H-bridge motor driver. While more complicated to drive, bipolar motors are much stronger for the same weight and size. Bipolar motors can be configured with series or parallel windings, allowing them to be driven with the lower current in series or higher inductance and greater torque in parallel. Bipolar motors generally have four or eight leads, two or four per phase, allowing them to be distinguished from the five and six-lead unipolar motors. FAQ 1. What is a stepper motor used for?The stepper motor is used for precise positioning with a motor, such as hard disk drives, robotics, antennas, telescopes, and some toys. Stepper motors cannot run at high speeds, but have a high holding torque. 2. What is a stepper motor and how does it work?Stepper motors are DC motors that move in discrete steps. They have multiple coils that are organized in groups called "phases". By energizing each phase in sequence, the motor will rotate, one step at a time. With a computer controlled stepping you can achieve very precise positioning and/or speed control. 3. What is the working principle of stepper motor?The basic working principle of the stepper motor is the following: By energizing one or more of the stator phases, a magnetic field is generated by the current flowing in the coil and the rotor aligns with this field. 4. Are stepper motors AC or DC?Stepper motors are DC motors that move in discrete steps. They have multiple coils that are organized in groups called "phases". By energizing each phase in sequence, the motor will rotate, one step at a time. With a computer controlled stepping you can achieve very precise positioning and/or speed control. 5. How long do stepper motors last?4.8 yearsThe typical lifetime for a stepper motor is 10,000 operating hours. This approximates to 4.8 years; given the stepper motor operates one eight-hour shift per day. The lifetime of a stepper motor may vary in regards to user application and how rigorous the stepper motor is run. 6. Do stepper motors need drivers?Stepper motors require a driver. There are usually 200 steps per revolution or 1.8 degrees per step (but they also can be “micro-stepped”). In general, you use an H-driver to reverse a DC motor, but it can also be done with a DPDT relay. 7. Do stepper motors go bad?Stepper motors very rarely go bad. It's possible, like a bearing fails. More often the wiring goes bad, or the stepper driver, or the driver overheats. 8. Why is it called stepper motor?Stepper motors are so named because each pulse of electricity turns the motor one step. Stepper motors are controlled by a driver, which sends the pulses into the motor causing it to turn. 9. What are the three types of stepper motor?There are three main types of stepper motors:Permanent Magnet Stepper. Variable Reluctance Stepper.Hybrid Syncronous Stepper. 10. How is stepper motor different from DC motor?The stepper motor operates in open loop whereas Direct current motor operates in closed loop. Stepper are are easy to control with the help of microprocessors and other controlling devices. Control of DC motor is not easy. ... DC motor has a continuous displacement and can be controlled accurately and positioned exactly.  11. Do stepper motors have brushes?Stepper motors are different from ordinary DC motors in at least four important ways. The first difference you notice is that they have no brushes or commutator (the parts of a DC motor that reverse the electrical current and keep the rotor—the rotating part of a motor—constantly turning in the same direction). 12. What voltage is a stepper motor?Stepper motors have a rated voltage and current. A typical stepper motor like our NEMA 17 might have a rated voltage of 2.8 Volts and a maximum current of 1.68 Amps. This basically means if you hook it up to 2.8 Volts it will draw 1.68 Amps. 13. Why do stepper motors fail?One of the major problems with a stepper motor is complete motor failure. This problem is caused by excessive current being sent to the device by the power supply. A short circuit in the wiring from the power supply to the motor cause this problem with the stepper motor. Some application will cause this short circuit. 14. Can stepper motors run continuously?Stepper motors fall somewhere in between a regular DC motor and a servo motor. They have the advantage that they can be positioned accurately, moved forward or backwards one 'step' at a time, but they can also rotate continuously. 15. How do I choose a stepper motor driver?A simple way to choose a stepper drive is to look for four things — voltage, current, microstepping, and maximum step pulse rate. Ensure that the drive can handle a wide range of current so that you can test the system at different voltage levels to fit your application.  

When you compare l1154f vs lr44, you need to know if you can swap one for the other in your device. The l1154f battery often looks similar to the lr44, but the l1154f uses a flat bottom while the lr44 has a domed bottom. This small difference can affect how the l1154f battery fits in your device and how well it works. Always check the battery compartment. Some devices need the l1154f battery shape to make proper contact. The l1154f battery gives reliable power, but only if you use the right l1154f for your device. Using the wrong l1154f battery may cause problems or poor performance.L1154F vs LR44: Are They Interchangeable?Battery CompatibilityWhen you look at l1154f vs lr44, you see that both batteries share the same size, voltage, and chemistry. This means you can usually use an l1154f battery in place of an lr44, or the other way around, in most devices. Major battery manufacturers recognize this compatibility and often list l1154, l1154f, and lr44 as equivalent models. You will also find other names like AG13, A76, and 357 for these batteries.Here is a quick comparison to help you understand their compatibility:Battery ModelChemistryVoltageSize (Diameter × Height)Manufacturer EquivalentsNotesLR44Alkaline1.5 V11.6 mm × 5.4 mmL1154, AG13, A76, 357, 157Interchangeable with L1154FL1154FAlkaline1.5 V11.6 mm × 5.4 mmLR44, LR1154, AG13, 157Interchangeable in most applicationsBoth batteries have a capacity of about 110–150 mAh and work well in many devices. Some lr44 batteries use silver oxide chemistry, which gives a more stable voltage and longer life. This can be important for devices like watches or calculators that need steady power. Most l1154f batteries use alkaline chemistry, which works well for toys, remote controls, and other devices with lower power needs.Tip: Always check your device manual before swapping batteries. Some devices need a specific chemistry for best performance.Device FitYou might wonder if the l1154f battery and lr44 will fit the same battery compartment. Both batteries have identical physical dimensions: 11.6 mm in diameter and 5.4 mm in height. This means they fit perfectly in any device designed for lr44 or l1154. Device manufacturers often list both l1154f and lr44 as compatible options in their manuals.Both batteries fit snugly in the same compartment.The shape and size ensure proper contact with the device terminals.You should always insert the battery with the correct polarity, as shown in your device instructions.Some devices, especially those with tight battery compartments, may work better with one brand or type due to small differences in the battery's bottom shape (flat or domed). However, for most devices, you will not notice any difference in fit or performance when using l1154f vs lr44.Note: Never mix old and new batteries or different chemistries in the same device. This can cause leaks or poor performance.You can trust that l1154f and lr44 batteries are interchangeable for almost all devices. Always follow the device compatibility guidelines in your manual to get the best results.Difference Between L1154 and LR44 BatteriesPhysical ShapeWhen you look at the difference between l1154 and lr44 batteries, you notice the physical shape first. Both the l1154f battery and lr44 have the same diameter (11.6 mm) and height (5.4 mm). This means you can usually use them as equivalent options in most devices. However, the l1154f battery often has a flat bottom, while the lr44 may have a slightly domed bottom. This small detail can affect how the l1154f fits in your device, especially if the battery compartment needs a certain contact shape.The l1154f battery’s flat bottom helps it sit securely in devices that require a stable connection.The lr44’s domed bottom can sometimes make contact easier in spring-loaded compartments.Always check your device’s battery compartment before choosing between l1154 and lr44.If your device manual lists the ag13 battery, a76 battery, or 357 as compatible, you can usually use the l1154f battery or lr44 as an equivalent.Voltage and ChemistryYou want your device to work reliably, so understanding voltage and chemistry matters. Both the l1154f battery and lr44 provide a nominal voltage of 1.5V under standard load conditions. The l1154f battery uses alkaline chemistry (zinc and manganese dioxide), which gives steady power for most small electronics. The lr44 can be either alkaline or silver oxide. Silver oxide versions, like the 357 or 357 silver oxide battery, offer a slightly higher voltage (1.55V) and keep their voltage stable until the battery is depleted.Here’s a quick comparison:FeatureL1154FLR44357 Silver OxideChemistryAlkalineAlkaline or Silver OxideSilver OxideNominal Voltage1.5 V1.5 V (alkaline), 1.55 V (silver oxide)1.55 VCapacity150–160 mAh110–130 mAh (alkaline)150–200 mAhVoltage StabilityGradually decreasesGradually decreases (alkaline), stable (silver oxide)StableLifespanShorterShorter (alkaline), longer (silver oxide)LongerThe l1154f battery stands out for its wide operating temperature range and enhanced leakage protection. This makes it a reliable alkaline button battery for many environments. The lr44, especially in silver oxide form, lasts longer and keeps voltage steady, which helps in devices like watches or calculators. If you need a cost-effective solution for toys or remotes, the l1154f battery or lr44 alkaline works well. For high-precision devices, the 357 or 357 silver oxide battery is a better choice.Tip: Always match the chemistry to your device’s needs. For everyday use, the l1154f battery and lr44 are reliable and affordable. For longer life and stable voltage, consider the 357 silver oxide battery.Choosing the Right BatteryDevice RequirementsYou need to match the l1154f battery to your device’s needs. Not all devices work the same way. Some require a specific voltage or battery chemistry to function properly. Before you select a replacement, check the battery compartment shape and contact design. Some devices need a flat-bottom battery, while others work better with a domed bottom. The l1154f battery and lr44 have the same size, but their chemistry and performance can differ.Here is a table to help you compare the most important device requirements for the l1154f battery and lr44:Device RequirementLR44 BatteryL1154F BatteryNominal Voltage1.5V suitable for devices needing 1.5V3.0V suitable for devices needing 3VShelf LifeApproximately 3 to 5 yearsUp to 10 years (longer shelf life)Temperature Range-10°C to +60°C-20°C to +60°C (better extreme temp performance)Physical Size11.6 mm diameter, 5.4 mm height11.6 mm diameter, 5.4 mm heightChemistrySilver oxide (Zn/Ag2O)Lithium-manganese dioxide (Li/MnO2)Capacity90-150 mAh160-200 mAh (higher capacity)PriceLower cost due to mass productionHigher cost due to lithium chemistryYou should always check the voltage your device requires. If your device needs 1.5V, both the lr44 and l1154f battery can work. If your device needs 3V, only the l1154f battery will fit the requirement. Shelf life matters if you store spare batteries. The l1154f battery lasts longer, so it is a good choice for emergency kits or devices you do not use often.Some devices, like calculators, thermometers, and small radios, use low power. The lr44 battery works well in these low-drain devices. The l1154f battery, with its higher capacity, can last longer in similar devices. For high-drain devices, you may need to look for best alternatives, as lr44 and l1154f batteries are not designed for heavy power use.Choose the l1154f battery for devices that need longer shelf life or higher capacity.Use lr44 for devices that need a lower-cost option and standard 1.5V power.Always check the battery compartment for fit and contact points.??? Tip: If you are unsure about the best replacement based on use case, check your device manual or look for l1154 equivalent batteries listed by the manufacturer.Manufacturer GuidelinesManufacturers want your devices to work safely and efficiently. They recommend using the battery type listed in your device manual. Most major brands say you can use lr44 as a direct replacement for the l1154f battery. Both batteries have the same size and voltage, so they are often interchangeable. You will also see l1154 equivalent batteries like AG13, A76, and 357 listed as best alternatives.Manufacturers do not warn against substituting l1154f for lr44 or vice versa. They do suggest you check for small differences in discharge characteristics and chemistry. In precision devices, like digital calipers or electronic micrometers, these differences can affect performance. For most everyday devices, you will not notice a difference.Always follow the device manual for battery replacement.Use reputable brands for reliable power.Do not mix old and new batteries or different brands in the same device.Recycle used l1154f batteries to protect the environment.?? Note: If your device needs stable voltage and long battery life, silver oxide batteries like the 357 may be the best alternatives. For most toys, remotes, and small electronics, the l1154f battery or lr44 will work as a safe replacement.You can trust that l1154f and lr44 batteries are safe to use in most devices. Always check the device requirements and manufacturer guidelines before choosing a replacement. This will help you get the best performance and longest life from your devices.Pros and Cons of Each BatteryL1154 BatteryYou often see the l1154 battery in watches, calculators, and small toys. The l1154f battery gives you steady power for low-energy devices. You can rely on the l1154f battery for everyday use because it has a low risk of leaking. The l1154f battery costs less than many silver oxide batteries, so you save money if you need to replace batteries often.Here is a table to help you see the main advantages and disadvantages of the l1154f battery:AspectAdvantages of L1154F BatteryDisadvantages of L1154F BatteryLifespanSuitable for low-energy devices; steady 1.5V outputShorter lifespan and lower capacity than silver oxide; not ideal for high-power devicesCostAffordable and budget-friendly compared to silver oxide batteriesFrequent replacements needed due to non-rechargeabilityReliabilityLow leakage risk due to alkaline chemistry; reliable for everyday low-power useSensitive to extreme temperatures; less reliable in harsh conditionsYou get a cost-effective solution with the l1154f battery. You should know that the l1154f battery does not last as long as silver oxide batteries. If you use your device in harsh conditions, the l1154f battery may not work as well. You cannot recharge the l1154f battery, so you need to replace it when it runs out.?? Tip: Choose the l1154f battery for devices that do not need high power or long battery life.LR44 BatteryThe lr44 battery works well in many devices. You find the lr44 in toys, remotes, and small electronics. The lr44 battery comes in both alkaline and silver oxide versions. You get a steady 1.5V output with the lr44 battery, which fits most devices that use button batteries.Here is a quick look at how the lr44 battery compares to the l1154f battery:FeatureLR44 BatteryL1154F BatteryChemistrySilver oxide (Zn/Ag2O)Lithium-manganese dioxide (Li/MnO2)Nominal Voltage1.5V3.0VCapacity90–150 mAh160–200 mAhShelf LifeAbout 3 to 5 yearsUp to 10 yearsOperating Temperature-10°C to +60°C-20°C to +60°CSealing & Leak RiskTypically sealed; may leak with ageSemi-sealed; better leak resistanceCostLow cost due to mass productionHigher cost due to lithium compositionAvailabilityVery commonly availableLess common, varies by regionUser SatisfactionPreferred for common, low-cost 1.5V devicesPreferred for devices needing 3V, longer life, and extreme temp performanceYou can find the lr44 battery almost anywhere. You pay less for the lr44 battery because it is mass-produced. The lr44 battery does not last as long as the l1154f battery in storage. You may see leaks in old lr44 batteries, so always check the expiration date. The lr44 battery works best in devices that need 1.5V and do not require long shelf life.?? Note: Pick the lr44 battery for devices that need a standard 1.5V battery and easy replacements.Best Battery for Device TypesWatches and ElectronicsYou often find l1154f and lr44 batteries in watches and small electronics. These batteries fit many devices because they share the same size and voltage. You can use lr44 batteries in most watches, calculators, and key fobs. The l1154f battery also works well in photography equipment and audio devices. Many people choose lr44 for watches because it is easy to find and costs less. If you need steady power for a device that runs all day, the l1154f battery gives you stable voltage and better leak resistance. Some precision watches and medical tools may work better with silver oxide batteries, but for most electronics, l1154f and lr44 batteries are reliable choices.Tip: Always check your device manual before you pick a battery. Some devices need a specific type for best results.Toys and GadgetsYou see l1154f and lr44 batteries in many toys and gadgets. Both batteries power small devices like remotes, electronic games, and novelty items. The l1154f battery stands out for its stable power and high leak resistance. This makes it a good choice for toys that get used often or left unused for long periods. The lr44 battery is budget-friendly and works well in low-power devices. If you want a battery that lasts longer and keeps your toys running smoothly, the l1154f battery is a smart pick.FeatureL1154 BatteryLR44 BatteryBattery TypeAlkaline, 1.5V button cellAlkaline, 1.5V button cellCapacity100-150 mAh110-150 mAhLeak ResistanceHighModerateBest UseToys, watches, medical tools, gadgetsToys, remotes, calculatorsMedical DevicesYou rely on batteries for medical devices like hearing aids and small monitors. The l1154f battery is common in these devices because it offers stable power and strong leak resistance. You can use lr44 batteries in some medical instruments, but the l1154f battery often gives better performance in sensitive devices. Outdoor gear and emergency tools also use l1154f batteries for their reliability. Always follow the device instructions to make sure you use the right battery for your health and safety.Note: For medical devices, never mix battery types or brands. Always use fresh batteries for the best results.L1154F vs LR44: Quick Comparison TableYou want to make the right choice for your device. This quick comparison table helps you see the main differences between the l1154f and LR44 batteries. You can use this table to decide which battery fits your needs best.FeatureL1154F BatteryLR44 Battery357 Battery (Silver Oxide)Size11.6 mm × 5.4 mm11.6 mm × 5.4 mm11.6 mm × 5.4 mmVoltage1.5V1.5V (alkaline)1.55VChemistryAlkalineAlkaline or Silver OxideSilver OxideBottom ShapeFlatDomed or flatFlatShelf Life3-5 years3-5 years5+ yearsCapacity110–150 mAh110–150 mAh150–200 mAhCompatibilityInterchangeable with LR44, 357Interchangeable with l1154f, 357Interchangeable with l1154f, LR44Typical UseWatches, toys, remotes, calculatorsToys, remotes, calculators, watchesWatches, medical devices, precision toolsYou can use the l1154f battery in many devices that also accept the LR44 or 357 battery. The l1154f battery works well in watches, toys, and small electronics. You may notice the flat bottom on the l1154f battery, which helps it fit in some battery compartments. The LR44 battery often has a domed bottom, but you can still use it in most devices that accept the l1154f battery.If you need longer life or stable voltage, you can use the 357 battery. The 357 battery uses silver oxide chemistry. This makes it a good choice for medical devices and precision tools. You should always check your device manual before you use a new battery type. Some devices work best with the l1154f battery, while others may need the 357 battery for better performance.?? Tip: Always match the battery shape and chemistry to your device. You can use the l1154f battery, LR44, or 357 battery in most cases, but checking the manual helps you avoid problems.When you choose between L1154F and LR44, focus on your devices’ needs. Both batteries fit most devices, but L1154F offers longer shelf life and higher capacity. You get better leak resistance and safety with L1154F, which helps your devices last longer. LR44 works well for everyday devices, especially if you replace batteries often. Always check your devices’ battery compartments and follow the manual. The table below shows how each battery performs in real-world devices.FeatureLR44 BatteryL1154F BatteryService LifeModerate to long, depends on loadVery long shelf life; low self-discharge (~2% per year)Capacity90–150 mAh (variant dependent)160–200 mAhShelf LifeApproximately 3 to 5 yearsUp to 10 yearsTemperature Range-10°C to +60°C-20°C to +60°CSealing StructureTypically sealed; may leak with ageSemi-sealed; better safety and leak resistanceImage Source: statics.mylandingpages.coFor most devices, L1154F gives you longer life and better safety. Always match the battery to your devices for the best results.FAQCan you use L1154F and LR44 batteries in the same devices?Yes, you can use both batteries in most devices. Both have the same size and voltage. Always check your devices’ manuals to make sure the battery fits and works well.Why does the battery bottom shape matter for devices?The bottom shape affects how the battery touches the contacts inside devices. Some devices need a flat bottom for a secure fit. Others work better with a domed bottom. Always look at your devices’ battery compartment before choosing.What happens if you use the wrong battery in your devices?If you use the wrong battery, your devices might not turn on or work right. The battery may not fit well. This can cause poor contact or even damage. Always match the battery to your devices’ needs.How do you know which battery is best for your devices?Check your devices’ manuals or look inside the battery compartment. The label often lists the right battery type. You can also search online for your devices’ model and battery recommendations.Can you mix old and new batteries in your devices?No, you should never mix old and new batteries in your devices. This can cause leaks or damage. Always replace all batteries in your devices at the same time for best results.

Warm hints: The word in this article is about 2500 and  reading time is about 12 minutes. The fiber optic sensor consists of the light source, incident fiber, exit fiber, light modulator, light detector, and demodulator. The basic principle is that the light of the light source is sent to the modulation area through the incident optical fiber, and the light interacts with the measured parameters in the modulation area to change the optical property of the light into the modulated signal light which is then sent through the outgoing fiber optical detector, demodulator and get the measured parameters. In recent years, sensors have evolved in the direction of sensitivity, precision, adaptability, compactness, and intelligence.  Optical fiber has many excellent properties, such as anti-electromagnetic interference and atomic radiation performance, soft and lightweight mechanical properties. Insulation, non-responsive electrical properties. Water, heat, and corrosion resistance of chemical properties, can reach people's eyes and ears in unattainable places (such as high-temperature areas), or in areas harmful to humans (such as nuclear radiation area), but also can transcend human physiological boundaries and receive sensory organs Unexpected outside information.   Catalogs I. Basic Structure and Principle of Fiber Optic SensorII. Application of Light Sensor in Petrochemical Industry2.1 The application of fiber optic sensor in the   petrochemical system2.2 The application of fiber optic sensor in oil   loggingIII. Application of Fiber Optic Sensors in Power Systems3.1 Applications in the high voltage cable temperature   and strain measurement3.2 Application in Electric Power Sensors3.3 Application of optical fiber cable monitoringIV. Fiber Optic Sensors in Medical Applications4.1 Pressure measurement4.2 Blood flow velocity measurement4.3 PH measurementV. Fiber Optic Sensor FeaturesFAQ  I. Basic Structure and Principle of Fiber Optic Sensor The fiber optic sensor consists of the light source, incident fiber, exit fiber, light modulator, light detector, and demodulator. The basic principle is that the light of the light source is sent to the modulation area via the incident fiber, and the light interacts with the measured parameters in the modulation area to make the optical properties (such as intensity, wavelength, frequency, phase, and normality) of the light occur Changes into a modulated signal light, and then sent through the optical fiber into the optical detector, demodulator to obtain the measured parameters. Fiber optic sensors can be divided into two categories by sensing principle: one is the light transmission (non-functional type) sensor, the other is the sensor type (functional) sensor. In the fiber optic sensor, the optical fiber only as a light transmission medium, the measured signal is detected by other sensitive components, this exit fiber, and the incident optical fiber is not continuous. Between the two Modulators are spectrally sensitive or other types of sensitive elements. In the sensing type fiber optic sensor, the optical fiber has both the sensitivity to the signal to be measured and the transmission of the optical signal. And the "sense" and "pass" of the signal are combined so that the optical fiber in such a sensor is continuous. Due to the different roles played by the optical fibers in these two sensors, the requirements for the optical fibers are also different. Optical fiber in the light-transmitting sensor only plays the role of light transmission. The use of communication fiber even ordinary multi-mode fiber can meet the requirements, and sensitive components can be a very flexible selection of high-quality materials. So the sensitivity of these sensors needs more optical coupling devices, the structure is more complex. The structure of sensing type fiber optic sensor is relatively simple with fewer coupling devices, but higher requirements on the optical fiber. It often needs to be sensitive to signal measurement, with good transmission characteristics. So far, most people adopt the former, but with the improvement of optical fiber manufacturing technology, sensor-type fiber optic sensors will also be widely used. According to the principle of light being modulated in optical fiber, fiber optic sensors can be divided into intensity modulation, phase modulation, polarization modulation, frequency modulation, wavelength modulation, and so on. Up to now, optical sensors have been able to measure more than 70 physical quantities. Fiber Optic Sensors have unique advantages over traditional sensors. (1) High sensitivity. Since light is a very short wavelength electromagnetic wave, its optical length is obtained by the phase of light. Taking an optical fiber interferometer as an example, due to the small diameter of the fiber used, its optical length is subject to slight mechanical external force or temperature change, causing a large phase change. Suppose that with a 10-meter optical fiber, a change of 1 ° C causes a phase change of 1000ard. If the minimum phase change that can be detected is 0.01ard, the minimum change in temperature that can be measured is 10 ° C, showing a high sensitivity. (2) Anti-electromagnetic interference, electrical insulation, corrosion resistance, intrinsically safe. Since fiber optic sensors transmit information using light waves, optical fibers are an electrically insulating, corrosion-resistant transmission medium and safe, which makes it easy and effective to use All kinds of large electromechanical, petrochemical, mine and other strong electromagnetic interference and flammable and explosive and other harsh environments. (3) Fast measurement. Light travels fastest and can transmit two-dimensional information, so it can be used for high-speed measurements. The analysis of radar and other signals requires an extremely high detection rate. The application of electronics is difficult to achieve. Using high-speed spectral analysis of light diffraction can be solved. (4) Large information capacity. The signal under test is a light wave carrier, and the light has a very high frequency. The contained frequency band is very wide. The same optical fiber can transmit multiple signals. (5) Suitable for harsh environments. Optical fiber is a dielectric, high voltage, corrosion-resistant, anti-electromagnetic interference that can be used for other sensors that do not adapt to the harsh environment. In addition, fiber-optic sensors are also characterized by their lightweight, small size, flexibility, wide measurement range, good reusability, and low cost. The application of fiber optic sensors is precise because fiber optic sensors have so many advantages, making it a very wide range of applications, involving petrochemicals, power, medicine, civil engineering, and many other fields. Video 1 Introduction of fiber optic sensorsII. Application of Light Sensor in Petrochemical Industry 2.1 The application of fiber optic sensor in the petrochemical systemIn the petrochemical system, due to the underground environment with high temperature, high pressure, chemical corrosion and electromagnetic interference, and other characteristics, the conventional sensor is difficult to play a role in the well. However, the fiber itself is no charge, small and light, easy to bend, anti-electromagnetic interference, and anti-radiation performance. Particularly it is suitable for flammable and explosive, strict restrictions and strong electromagnetic interference, and other harsh environments. Fiber optic sensors in the measurement of the good parameters play an irreplaceable role. It will become the oil and gas exploration and oil logging and other logging A field of broad market prospects of new technologies.  Fiber optic sensor application in oil and gas exploration. Because of its high-temperature capability, multi-communications, distributed sensing capabilities, and the fact that it requires only a small space to meet its use conditions, fiber optic sensors make it particularly unique in exploration drilling. The application of fiber optic sensors can be made into the downhole spectrometer, distributed temperature sensor, and optical fiber pressure sensor, and other products suitable for this special job requirement. (1) The downhole spectrometer fluid analyzer shown in Figure 1 can be used to understand the crude oil composition during the initial development process. It consists of two sensors: one is the absorption spectroscopy fiber and the other is the fluorescence and gas detector. Downhole fluid is introduced into the tubing by formation probes and the optical sensor is used to analyze the fluid within the tubing. Fluid analysis spectrometers provide in-situ downhole fluid analysis and improve formation fluid evaluation. (2) Distributed temperature sensors. Optical fiber distributed temperature sensors are the most popular fiber optic sensors for downhole applications. The application example is to monitor the steam injection heavy oil recovery system. Steam is injected into the heavy oil reservoir to reduce the viscosity of the oil, allowing heavy oil to be mined out. Downhole steam temperature can be as high as 250 ℃. Figure 1 Fluid analyzer structure(3) The fiber-optic pressure sensor is currently under development. Its main focus is on ultra-high temperature and downhole pressure monitoring tasks. Other commercial products based on fiber optic sensors are currently available. For example, fiber optic probes for multiphase flow measurements and distributed dynamic strain measurements. Its high reliability, high efficiency, and low power consumption are key factors in the success of optical fiber products in oil field applications. 2.2 The application of fiber optic sensor in oil loggingOil logging is one of the most basic and key aspects of the petroleum industry. The parameters such as pressure, temperature, and flow rate are important physical quantities in oil and gas wells. These advanced technologies are used for long-term Real-time monitoring, timely access to the information of oil and gas wells, the oil industry has a very important significance. Fiber optic sensors are insensitive to electromagnetic interference and withstand extreme conditions, including high temperatures and pressures, as well as strong shock and vibration, to measure borehole and well site environmental parameters with high accuracy, and have distributed measurement capabilities for fiber optic sensors. The spatial distribution gives the profile information. Moreover, the fiber optic sensor cross-sectional area is small, short in shape, in the wellbore occupies a very small space. Traditional electronic sensors do not have such features in the harsh underground environment. Fiber optic sensors can do downhole flow measurement, temperature measurement, pressure measurement, water (gas) measurement, density measurement, acoustic measurement. (1) Flow measurement. Because the intensity, phase, frequency, wavelength, and other characteristics of light in the optical fiber transmission process will be subject to flow modulation. A certain light detection method can convert the modulation into electrical signals, you can find the fluid flow, which is the fiber flow the working principle of the meter. (2) Temperature and pressure measurement. The distributed optical fiber measurement system (DTS) utilizes the Raman effect of the optical fiber to enable real-time monitoring of the temperature field where the fiber is located. The EFPI type (non-intrinsic FP interference) and FBG fiber optic sensors are wavelength-coded sensors. With high sensitivity, it also can simultaneously measure pressure, temperature, stress, and other parameters of the characteristics. The optical fiber thermal color temperature sensor is a reflective temperature sensor composed of a white light source and a multi-mode optical fiber.  The optical fiber radiation temperature sensor utilizes black body radiation energy. Its non-contact, measurable instantaneous temperature, fast response, and no need for heat balance time are available. In high-temperature measurement, the semiconductor absorption-type optical fiber temperature sensor utilizes the characteristic that the absorption edge wavelength of its semiconductor material shifts to a longer wavelength as the temperature increases, and an appropriate semiconductor light-emitting diode is selected so that its spectral range falls exactly on the absorption edge region. , So the light intensity through the semiconductor decreases with increasing temperature. (3)Water (Gas) Rate and transmission power of U-shaped fiber used for density measurement vary with the refractive index of the external medium. The lightwave serves as an information carrier and has nothing to do with the resistivity, flow pattern, and water quality of the mixed fluid. The fiber holding rate is based on this principle. The density sensor essentially solves the problem of the application of high water content without resolution and radioactive substances in the existing holding ratios. For the multi-phase fluids, the refractive indices of oil, water, and gas are all different, so the refractive index of the mixed fluid will follow. Change the ratio of oil, water, gas changes. Therefore, this refractive index modulation type fiber optic sensor can not only measure the fluid holding rate, fluid density can be measured at the same time, for its accuracy is higher. (4) Sonic measurement. Seismic waves propagate in different media and the waveforms of the received seismic waves will be different. According to different seismic waveforms, the sedimentary sequence and sedimentary structure can be identified to locate the reservoir, determine the gutter, detect the damage and fracture of the casing, and perforation, detect layers and determine the fluid flow, and so on. VSP seismic logging means that the geophone is placed in a well and the seismic signal is received by the geophone in the well by means of a micro-vibration generated by ground-derived seismic waves or fluid flow in the well.  The permanent downhole optical fiber three-component seismic survey has high sensitivity and directionality can produce high-precision spatial images. It can not only provide near-borehole images but also can provide strata images around the wellbore. And the measurement range can reach thousands of kilometers. It withstands harsh environmental conditions and has no moving parts and downhole electronics that can withstand strong shocks and vibrations and Can be installed in an extremely small space for complex completion string.  III. Application of Fiber Optic Sensors in Power Systems Because of the complicated structure and wide distribution of power system networks, various hidden dangers exist on the high-voltage power line and power communication network. Therefore, it is very important for distributed monitoring of various lines and networks in the system.  3.1 Applications in the high voltage cable temperature and strain measurementAt present, foreign countries (mainly Britain, Japan, etc.) have developed the distributed optical fiber temperature sensor products by utilizing the laser Raman spectroscopy effect. And domestically, we are actively carrying out research work in this area. The domestic begin to introduce the distributed optical fiber temperature sensing technology into the power system cable temperature measurement. In connection with the snow disasters suffered in southern China last year, we can consider that if we can lay sensor fiber optic cables in parallel on high-voltage cables and measure the temperature, pressure, and other parameters of power system cables and towers in real-time, we can make timely measurements, so as to minimize economic losses.  Fiber optic sensors in the power system will have a wide range of applications. Ideally, the fiber should be placed as close as possible to the cable core to more accurately measure the actual cable temperature. For direct-buried power cables, although the surface-mount fiber can not accurately reflect the change of cable load, it is more sensitive to the change of thermal resistivity of soil in the buried cable and can reduce the installation cost of optical fiber. 3.2 Application in electric power sensorsElectric power is the basic power reflecting the energy conversion and transmission in the power system. Electric power measurement is an important part of power metering. With the rapid development of the power industry, traditional electromagnetic measurement methods have increasingly exposed their inherent limitations, such as electrical insulation, electromagnetic interference, and magnetic saturation.  Therefore, people have been working hard to find new methods for measuring electrical power. It can be said that the advent of fiber optic sensors has brought people the gospel to solve this problem. The main characteristics of fiber-optic power sensors are: Since electric power sensing involves both voltage and current at the same time, it is usually necessary to consider both electro-optic and magneto-optic effects. At the same time, two kinds of sensing media or one multifunctional media are used as sensitive elements. The structure of the fiber electric power sensor head is relatively complicated; the optical sensor signal of the fiber electric power sensor sometimes includes voltage and current signals at the same time, so the signal detection and processing methods thereof will also be more complicated. 3.3  Application of optical fiber cable monitoringIn Power Systems The power system has a wide variety of optical cables. In addition, China has a vast area and the environment varies widely. Therefore, the environment of optical cables is also very complex. Temperature and stress are the main environmental factors that affect the performance of optical cables. Therefore, while monitoring the breakpoint of the optical fiber, the temperature and stress conditions of the optical cable are also monitored. It can be seen that the optical fiber cable has far-reaching fault warning and maintenance.  By measuring the frequency shift and intensity of the Brillouin scattered light along the length of the optical fiber, the temperature and strain information of the optical fiber can be obtained, and the sensing distance is relatively long, so it has far-reaching engineering research value. Based on Brillouin Optical Time Domain Reflectance (BOTDR) distributed optical fiber sensing system, using coherent detection technology, the system principle shown in Figure 2.  Figure 2 based on BOTDR sensing system principleThe BOTDR fiber sensing system measures the self-distribution of scattering signals of an optical fiber and its signal strength is very weak, but the coherent detection technology can be used to improve the signal-noise ratio of the system. This solution can be a single light source, single-ended work, the system is simple and easy to implement, and can simultaneously detect fiber breakpoints, loss, temperature, and strain.  IV. Fiber Optic Sensors in Medical Applications In medical fiber, sensors are mainly light-transmitting. With its small size, insulation, non-radio frequency, and microwave interference, high measurement accuracy and good affinity with living organisms, and other advantages. This article will mainly introduce the application of transmission optical fiber in pressure measurement, blood flow velocity measurement, and pH measurement. In addition, it can also be applied to the measurement of temperature and medical image transmission. 4.1 Pressure measurementCurrent clinically applied pressure sensors are mainly used to measure intravascular blood pressure, intracranial pressure, intracardiac pressure, bladder, and urethral pressure. The pressure sensor used to measure blood pressure is schematically shown in Figure3. The pressure-sensitive part is a water-repellent film on the sidewall of the tip of the probe catheter connected to the membrane by a cantilever micromirror and an optical fiber opposite the reflector for transmitting incident light to the reflector while The reflected light is also transmitted.  When there is pressure on the film, the film is deformed and can drive the cantilever to change the angle of the mirror. The light beam coming from the fiber is shone on the mirror and then reflected at the end of the fiber. Since the direction of the reflected light changes with the angle of the mirror, the intensity of the reflected light received by the optical fiber also varies. This change passes through the optical fiber to the other end of the photodetector into an electrical signal, so that by changing the voltage to know the size of the probe at the pressure.Figure 3 Optical fiber pressure gauge probe 4.2 Blood flow velocity measurement Doppler-type optical fiber speed sensor measurement of subcutaneous tissue flow velocity shown in Figure 4, this device uses the optical fiber end reflection phenomenon, the measurement system is simple in structure.Figure 4 optical fiber pressure gauge probeLaser light with a frequency of f passes through the lens and the fiber is sent to the epidermal tissue. For immobile tissue, such as the vessel wall, the reflected light does not produce a frequency shift; and for the red blood cells in the cortex capillary flow rate, the reflected light to produce a frequency shift, the frequency change △ f. The frequency shift of the reflected light The intensity is proportional to the concentration of erythrocytes and the change in frequency can be proportional to the velocity of erythrocytes. Emitted light collected by the optical fiber, the first on the light detector for mixing, and then into the signal processing instrument, which get the red blood cell velocity and concentration. 4.3 PH measurementA schematic diagram of the pH fiber optic sensor used to determine tissue and blood values is shown in Figure 4. Its working principle is the use of emission light, the intensity of transmitted light with the wavelength distribution of the spectrum to be measured. The sensor inserts two optical fibers into an ion-permeable cellulose capsule containing reagent, which penetrates the reagent when the needle is inserted into the tissue or blood vessel, causing the reagent to absorb light of a certain wavelength. Measured such changes, you can get the blood or tissue pH.Figure 5 Determination of pH fiber spectrometerV. Fiber Optic Sensor Features 1.High sensitivity. 2.The geometry has a wide range of adaptability, can be made into any shape of the fiber optic sensor. 3.You can create sensors sensing a variety of different physical information (sound, magnetic, temperature, rotation, etc.) of the device. 4.Can be used for high voltage, electrical noise, high temperature, corrosion, or other harsh environments. 5.But also with the inherent compatibility of optical telemetry technology. The advantages of fiber-optic sensors are that optical fiber sensors use light as a carrier for sensitive information, and use optical fibers as a medium for transmitting sensitive information. Compared with conventional sensors. They have the characteristics of optical fiber and optical measurement and have a series of unique advantages. Good electrical insulation, anti-electromagnetic interference, non-invasive, high sensitivity, easy to achieve long-distance monitoring of the signal under test, corrosion resistance, explosion-proof, flexible optical path, easy to connect with the computer. Sensors are developed in the direction of sensitivity, precision, adaptability, compactness, and intelligence. They can serve as human eyes and ears where people cannot reach(such as high-temperature areas, are as harmful to humans, or nuclear radiation areas). But it is also beyond the physical boundaries of human beings, outsiders can not feel the sensory information. FAQ 1. How does a fiber optic sensor work?Fiber optic sensors work based on the principle that light from a laser or any superluminescent source is transmitted via an optical fiber, experiences changes in its parameters either in the optical fiber or fiber Bragg gratings and reaches a detector which measures these changes. 2. What are fiber optic sensors used for?Optical fibers can be used as sensors to measure strain, temperature, pressure and other quantities by modifying a fiber so that the quantity to be measured modulates the intensity, phase, polarization, wavelength or transit time of light in the fiber. 3.How are fiber optic sensors classified?Based on the operating principle or modulation and demodulation process, a optical fiber sensor can be classified as intensity, a phase, a frequency, or a polarization sensor. All these parameters may be subject to change due to external perturbations. ... These sensors are widely used as chemical sensors. 4. What is active and passive optical fiber sensor?Active fibre optic. -In optical fiber communication, because the signal usually decades during long distance transformation, you need to add an amplifier to boost the signal. Passive fibre optic. - Simply receive light data from the environment, it is commonly used for illumination (Fiber optical lighting. 5. What are the characteristics of optical fiber sensors?Optical fiber sensors have unique advantages, such as high sensitivity, immunity to electromagnetic interference, small size, light weight, robustness, flexibility, and the ability to provide multiplexed or distributed sensing. 6. Which is a use of fiber optics?They are widely used in lighting, both in the interior and exterior of vehicles. Because of its ability to conserve space and provide superior lighting, fiber optics is used in more vehicles every day. Also, fiber optic cables can transmit signals between different parts of the vehicle at very fast speed. 7. Why optical fiber is used for communication?Optical fiber is used by telecommunications companies to transmit telephone signals, Internet communication and cable television signals. ... Due to lower attenuation and interference, optical fiber has advantages over copper wire in long-distance, high-bandwidth applications. 8. Is fiber optic WIFI?Like any Internet service, fiber optic Internet download speeds depend on your connection. Not all fiber services are created equal, much like broadband. ... You can download more, faster, with fiber. Fiber Internet is more reliable than copper and less 'patchy' than Wifi. 9. Is fiber optic analog or digital?Digital signals can be transmitted long distances without degradation as the signal is less sensitive to noise. Fiber optic datalinks can be either analog or digital in nature, although most are digital. Both have some common critical parameters and some major differences. 10. How much data can a fiber optic cable transmit?A new fiber-optic system can carry 800 gigabits of data per second, a big step up from top speeds of 100 or 200 gigabits in today's data centers. You May Also Like:GPS and inertial sensors for driverless applicationsA New Technology for Advancing Opticals,Sensors Even Resistant SupercapacitorsSensors are Always In a State of Rapid Progress