The Kynix Blog

Introduction In the FOC(Field Oriented Control) algorithm, the sampling current is the basis of the algorithm implementation and a very important part. So accurate current sampling can bring better result to the algorithm. In other words, if the current sampling is accurate, it will be very helpful for the subsequent coordinate transformation to obtain required results. From this we can see the role of current sampling in the entire FOC algorithm. Understanding Field-Oriented Control Catalog Introduction Ⅰ Current Sampling Method Ⅱ Three Sampling Methods and Precautions 2.1 Single-resistor Sampling 2.2 Dual-resistor Sampling 2.3 Triple-resistor Sampling Ⅲ The Key to Sampling Ⅳ Delay Source Ⅴ Delay Type and Typical Time Ⅵ Analysis in Details 6.1 PWM Dead Time Insertion 6.2 Optocoupler Delay and Pre-Driver Delay 6.3 Transistor Switching Delay 6.4 Other Delays Ⅶ FAQ Ⅰ Current Sampling Method In motor control, the current sampling method is generally to use PWM to trigger ADC to convert. Taking SoC(System-on-a-Chip) as an example, the ADC module will be configured to automatically sample and trigger conversion. When the trigger point set by the PWM module matches, the signal will be given to the ADC module. At this time, the sampling switch in circuit will be disconnected, and then the ADC module will start to convert, and the voltage of the corresponding sampling current can be obtained after the conversion is completed. The AD value of the signal, you can use this value in the program to write and verify the algorithm. Figure 1. Current Sampling Time Ⅱ Three Sampling Methods and Precautions Current sampling is the basis of FOC, including current sensor sampling and resistor sampling. Resistor sampling is widely used for its simple and low-cost characteristics. The method includes single-resistor sampling, dual-resistor sampling, and triple-resistor sampling. 2.1 Single-resistor Sampling The biggest difference between the single-resistor and the other two methods is that it cannot obtain two current signals at the same time. Even if two current signals are obtained, there is an error in estimating the third current signal. The formula Iu+Iv+Iw=0 is conditional, that is, the three currents must be recorded at the same time. When the inductance of the motor is larger, the two currents obtained are closer to the real situation. When the inductance is small, the deviation may be relatively large. So if the inductance of the current is large, single-resistor sampling can be selected.This method requires two samplings in one PWM cycle. In this case, it is necessary to analyze the switch state in the algorithm to clarify which phase current the reconstructed current corresponds to at the time of sampling. 2.2 Dual-resistor Sampling In the case of dual-resistor sampling, the sampled two-phase current must be used directly. Even if there is a deviation, it needs to be used. This method cannot be used to calculate the third-phase current based on the other two-phase sampling like the triple-resistor sampling. That is to say, this method needs to consider the problem of the sampling window. If the sampling current is to be guaranteed to be accurate, the sampling window must be large enough. To make the sampling window large enough, the PWM waveform needs to be deformed. But this will increase the execution time of the algorithm. The advantage of this approach is to reduce a current-sense resistor and an op amp.As shown in the figure below, the front of the red circle is the oscillating area. If the sampling window is small, only the oscillating area will not be able to obtain an accurate current. To process the sampling window, you can refer to the following figure, so that the obtained current will be more accurate. Figure 2. Current Sampling Zone 2.3 Triple-resistor Sampling This method is the simpler among the three methods. It directly uses three current-sensing resistors to sample the three-phase phase current of the motor, and the result obtained in this way is relatively straightforward. Using the formula Iu+Iv+Iw=0, recalculate the phase current of one phase with a small sampling window. So that the accuracy of the result obtained is the highest, and the implementation of the following related algorithms is easier. It is the advantage of this method. However, three current-sense resistors and three op amps are used, the hardware cost will be higher than the other two.   Ⅲ The Key to Sampling The current sampling includes peak current and average current sampling. Generally, the most common is the average current sampling and its control, so there are actually two ways to sample the average current. One is that the current-sense resistor is placed on the upper bridge of the inverter bridge. The other is that the current-sense resistor of the inverter bridge is connected to the lower end of the lower bridge.The general method is the latter. The current detection circuit corresponding to this method is relatively simple, and the corresponding power consumption will also be reduced. In this case, the freewheeling current is collected at the lower end, and then we can sample at the midpoint of the lower bridge opening. At this time, the corresponding current reflects the average current, so the corresponding current control is the average.Then, if we use the three-resistor sampling method, the selected ADC module must have at least the function of simultaneous sampling of three channels. So as to ensure that the three-phase currents obtained by sampling are the currents at the same time, and at this time, to meet the condition, Iu+ Iv+Iw=0.In the case of dual-resistor sampling, there are only two sampling resistors, and the obtained current cannot use the formula Iu+Iv+Iw=0. Therefore, even if the sampling window is small, if the algorithm is not processed, the double-resistor scheme has limitations. In order to get a better adaptation to the scene, algorithm compensation must be performed on the dual-resistor method, which is also the key point of it.Similarly, for the single-resistor sampling way, the corresponding current needs to be obtained according to different switch combinations, and it needs to be sampled twice in a PWM cycle. This method cannot satisfy Iu+Iv+Iw=0, and can only be determined by an algorithm. Compensation and correction are performed, so the single-resistor method is more difficult to take. However, if the difficulty can be solved, this method is the best and cheapest one.   Ⅳ Delay Source During the development of the motor-driven FOC control, have you encountered the situation that the motor is too noisy, inefficient or even unable to operate? All of this may be due to sampling anomalies of the phase currents, resulting in the inability to reconstruct the correct three-phase currents in the FOC algorithm. Here is an analysis of a factor that affects current sampling: the delay source.In the motor drive FOC control of double-resistor sampling, the sampling point is set as the middle moment when the lower tube of the drive bridge is turned on. Note that this is the middle moment when the lower tube of the drive bridge is turned on, not the middle moment of the PWM cycle output by the MCU. There are as many as seven delay sources in this typical drive topology because the PWM is calculated from the MCU to the ADC module where the current signal is sent to the MCU. Figure 3. MCU Output Ⅴ Delay Type and Typical Time The table below details the seven sources of delay that exist in motor drive system topologies and their typical timings. These delays will be superimposed together, and the effect is that the actual output PWM waveform lags behind the PWM waveform that the MCU calculates the expected output. According to this calculation, the phase current sampling point needs to lag the middle moment of the MCU calculating the expected output PWM waveform. Delay Type Typical Time PWM Dead Time Insertion 100ns-2μs Optocoupler Isolation to Pre-driver 40ns-300ns Pre-driver Switch Delay About 50ns MOSFET Switching Time 100ns-1μs Amplifier Delay <1μs Low-pass Filter Delay 1-2μs ADC Delay 50ns-200ns   Ⅵ Analysis in Details 6.1 PWM Dead Time Insertion In the three-phase brushless motor drive system, three bridge arms are required to control the current flow of the phase line, and there are two power devices on each bridge arm, such as MOSFET and IGBT. The pair of power devices cannot be turned on at the same time, otherwise a short circuit will occur. Here MOSFET is used as a power device to illustrate. In the control, dead time must be inserted to ensure that the upper and lower MOSFETs are not turned on at the same time. Typical values of dead time may be between 100ns and 2μs, depending on various factors in the system, such as MOSFET drive voltage and type.After the required PWM waveform is inserted into the dead time, what you get is that both the PWM midpoint and the rising edge are shifted to the right. When using the FOC control algorithm calculates the proper PWM, we start seeing the first delay, recording the dead time. Figure 4. Dead Time Insertion 6.2 Optocoupler Delay and Pre-Driver Delay The signal response of the various optocouplers and pre-drivers causes additional delays between the moment the MCU controls the FTM module to output the PWM waveform and the moment the MOSFET gate is controlled. The output of the pre-driver is delayed by a period of time (Delay1) compared to the waveform output from the MCU pins. Figure 5. Delay 1 6.3 Transistor Switching Delay Through the pre-driver, the PWM waveform reaches the MOSFET transistors, but due to their inherent characteristics, all transistors take a certain amount of time to turn on and off. This delay time varies depending on the transistor type and the voltage level required to switch between on/off. Delay 2 is the total delay between the theoretical switching point (CMP2) of the phase line voltage and the instant of the actual switching point. Figure 6. Delay 2 Finally, the gate voltage reaches the level that can make the transistor turn on, the current passes through the phase line and the sampling resistor, and a voltage difference is generated across the sampling resistor. The red waveform is the phase current waveform in an ideal state. At this time, there is a total delay time between the midpoint of the PWM cycle calculated and generated by the MCU, and the "phase current midpoint shift" is shown in the figure. Figure 7. Phase Current Midpoint Shift 6.4 Other Delays As shown in the figure below, the final delay chain that affects the current sampling is formed by the amplifier slew rate, the low-pass filter on the MCU pins, and the ADC slew rate. The time marked by the red circle in the figure is the correct current sampling time. It can be seen that the phase current sampling point is greatly delayed compared with the PWM midpoint output by the FTM. Figure 8. Other Delay In all and electrical and electronic circuits, there will be signal delay problems. And it is impossible to completely eliminate them, but the impact can be reduced by selecting low-delay devices. In the motor drive, in addition to selecting the appropriate device, it is also necessary to perform software compensation for the signal delay. The precise delay time of these delay sources mentioned in the article can be obtained by oscilloscope and calculation, and the correct current sampling time can be obtained by compensating for these delays in software. In this way, the data collected at the correct moment can be used as the data source for reconstructing the three-phase current of the motor in the FOC control.   Ⅶ FAQ 1. What is FOC algorithm?Field-oriented control (FOC), or vector control, is a technique for variable frequency control of the stator in a three phase AC induction motor. 2. What is FOC drive?Vector control, also called field-oriented control (FOC), is a variable-frequency drive (VFD) control method in which the stator currents of a three-phase AC or brushless DC electric motor are identified as two orthogonal components that can be visualized with a vector. 3. What is FOC brushless motor?FOC implementation allows the BLDC motor to run more efficiently (high power factor and better light load efficiency), more smoothly (lower torque ripples) with quick dynamic response (better dynamic performance to load and speed changes). 4. What is FOC in BLDC motor?Field oriented control (FOC) is an important control approach for Brushless DC motors. It resembles sinusoidal commutation but adds a major mathematical twist. Figure 3a shows control schemes for both sinusoidal commutation and field oriented control. 5. How is Bldc phase current measured?With a BLDC motor use an ac voltmeter to measure the voltage between any 2 wires of the 3 motor wires and then convert the line-to-line voltage to the phase voltage value by dividing the line-to-line voltage by 3 =1.73. 6. Do BLDC motors have inrush current?Handle Peak Inrush Current of a BLDC Motor to protect the Power Supply. Summary: BLDC motors have a Peak current on startup which is 3x or more the rated current. The motor has a rated current of 7.3A. 7. What causes motor inrush current?When an electrical device, such as an AC induction motor, is switched on, it experiences a very high, momentary surge of current, referred to as inrush current. ...The interaction of these two magnetic fields produces torque and causes the motor to turn.

    Circuit protection is a frequently discussed topic, and the various types of circuit protection differ due to the various problems in the circuit. Short-circuit, overload, grounding, and lightning strikes are the most common faults in power supply systems. To ensure the safe and dependable operation of the power supply system, protection devices must be installed to monitor the working conditions of the power supply system, detect faults in time, and cut off the power supply of the faulty equipment, preventing the accident from spreading. In general, the protection circuit is made up of various relays, signal indicating devices, and other components. This blog provides an in-depth discussion on several circuit protections. Below is an introduction video about short circuit protection. DIY Short Circuit (Overcurrent) Protection   Catalog   I Introduction to circuit protection II Switching power principle and characteristics      2.1 Operational principle of switching power      2.2 Characteristic of switching power III DC Switching power supply protection      3.1 Overcurrent protection circuit      3.2 Overvoltage protection circuit      3.3 Soft start protection circuit        3.4 Overheat protection circuit IV Conclusion FAQ   I Introdcution to circuit protection The operation of electronic equipment can not be separated from electricity, so DC switching power supply which can control the electricity is playing a more and more important role. And it has entered various fields of electronics and electrical equipment: SPC exchange, communication, electronic testing equipment power supply and controlling equipment power supply, which are widely used DC switching power supply.  Meanwhile, with the development of many high-tech technologies, including high-frequency switching technology, soft-switching technology, power factor correction technology, synchronous rectifier technology, intelligent technology, surface installation technology, etc., switching power supply technology is constantly innovating. This provides a wide range of development for DC switching power supply.  DC current diagram   But the circuit is complex to control in the switching power supply, the transistor and the integrated device have poor resistance to electricity and thermal shock, which brings great inconvenience to the user in the process of using. In order to protect the safety of switching power supply itself and load, the overheat protection, over-current protection, over-voltage protection and soft start protection circuit are designed according to the principle and characteristics of DC switching power supply.   II Switching power principle and characteristics 2.1 Operational principle of switching power DC switching power supply is composed of input part, power conversion part, output part and control part. The power conversion part is the core of the switching power supply. It performs conversion which needed for the output on the high-frequency and unstable DC. It is mainly composed of switching transistor and high frequency transformer. Figure 1. DC Switching power supply principle Figure 1 shows the schematic diagram and equivalent schematic block diagram of DC switching power supply, which is composed of full wave rectifier, switching tube V, excitation signal, fly-wheel diode Vp, energy storage inductance and filter capacitance C. In fact, the core part of DC switching power supply is a DC transformer. 2.2 Characteristic of switching power   In order to meet the needs of users, the world's major switching power supply manufacturers are committed to the simultaneous development of new and highly intelligent components, especially by reducing the loss of the secondary rectifier. In order to improve the magnetic properties under high frequency and high magnetic flux density, power ferrite (Mn-Zn) materials have been developed. At the same time, the application of SMT technology in the field of switching power supplies has also made considerable progress. The components are arranged on both sides of the circuit board to ensure that the switching power supply is light, small and thin. Therefore, high frequency, high reliability, low power consumption, low noise, anti-interference and modularization are the development trends of DC switching power supplies. However, DC switching power supplies also have disadvantages. The DC switching power supply switch has serious interference, and its ability to adapt to harsh environments and sudden failures is weak. There is still a certain gap in microelectronics technology in developing countries. Specifically, the production technology of resistors and capacitors and the technology of magnetic materials are compared with those of some technologically advanced countries. Therefore, the manufacture of DC switching power supplies is very difficult. In most parts of the world, maintenance is difficult and the cost is high. III DC Switching power supply protection Based on the characteristics of DC switching power supply and the actual electrical condition, in order to make DC switching power supply work safely and reliably in bad environment and sudden fault, this paper designs a variety of protection circuits according to different conditions. 3.1 Overcurrent protection circuit   Figure 2. Input Overcurrent protection circuit In DC switching power supply circuit, in order to avoid short circuit and overflow damage to protect the regulator tube in the circuit, the basic method is that, when the output current exceeds a certain value, the regulator tube is in the reverse bias state, thus the circuit current is cut off automatically. As shown in Fig. 2, the over-current protection circuit consists of transistor BG2 and divider resistor R4, R5. When the circuit works normally, the base potential of BG2 is lower than that of emitter through the partial voltage interaction between R4 and R5, and the emitter junction bears reverse voltage. So the BG2 is in the cutoff state (equivalent to open circuit), which is used to stabilize the voltage. But the voltage stabilizing circuit has no effect. When the circuit is short circuit, the output voltage is zero and the emitter of BG2 is equivalent to grounding, then the BG2 is in the state of saturation conduction (equivalent to short circuit), so that the regulator tube BG1 base and emitter are close to short circuit, and in the cut-off state, the circuit current is cut off to achieve the purpose of protection.   3.2 Overvoltage protection circuit The overvoltage protection of switching regulator in DC switching power supply includes input overvoltage protection and output overvoltage protection. If the voltage of the unstabilized DC power supply (such as batteries and rectifiers) used by the switching regulator is too high, it will cause the switching regulator to fail to work properly and even damage the internal devices. Therefore, it is necessary to use the input overvoltage protection circuit in the switching power supply. Fig. 3 is a protection circuit composed of transistors and relays, in which the voltage of the input DC power supply is higher than the breakdown voltage of the zener diode, at this condition, current flows through resistor R, making diode T conducts. Following these electrical actions, relay operates and common closed contact disconnected, inputting current. The polarity protection circuit of the input power supply can be combined with the input overvoltage protection to form the polarity protection identification and overvoltage protection circuit. Figure 3. Input overvoltage protection circuit 3.3 Soft start protection circuit The circuit of switching power supply is complex, the input end of switching regulator is usually connected with small inductance and large-capacitance input filter. At start-up instant, the filter capacitor flows through a large surge current that can be several times the normal input current. Such a large surge current melts the contacts of the normal power switch or the relay and melts the input fuse. In addition, surge current can also damage capacitors, shorten their life, cause premature damage. To this end, a current-limiting resistance should be connected in the circuit, through this current-limiting resistance to charge the capacitor. In order not to consume too much power by the current limiting resistance, and avoid affecting the normal operation of the switching regulator, therefore a relay is used to connect it automatically after the transient process is finished, which makes the DC power supply directly to the switching regulator. This is called the "soft start" circuit of DC switching power supply. Figure 4. Soft start-up protection circuit When the power supply is switched on, capacitor C is charged by input voltage through rectifier bridge (D1 ~ D4) and current-limiting resistance R1 to limit the surge current. The inverter works normally when the capacitor C is charged to about 80% rated voltage. The trigger signal of thyristor is generated by auxiliary winding of main transformer, which makes thyristor switch on and short circuit current-limiting resistance R1, and the switching power supply is in normal operation state. In order to improve the accuracy of the delay time and prevent the relay operation from shaking and oscillating. The delay circuit can replace the RC delay circuit by the circuit shown in figure 4(b). 3.4 Overheat protection circuit The high integration and light weight of switching regulator in DC switching power supply greatly increase the power density per unit volume, so if the internal components of the power supply do not have a corresponding increase in the temperature of its working environment, it will inevitably make the circuit performance damaged and components life service shortened prematurely. Therefore, overheating protection circuit should be installed in high power DC switching power supply. Figure 5. Overtemperature protection circuit In this paper, the temperature relay is used to detect the internal temperature of the power supply device. When the inside of the power supply device is overheated, the temperature relay operates, which makes the alarm circuit of the whole machine in the state of alarm and realizes the protection of the overheating of the power supply.  As shown in Fig. 5 (a), the P type control gate thermal thyristor is placed near the power switch transistor in the protection circuit. According to the characteristics of the TT102 (the on-on temperature of the device is determined by the Rr value, the larger the Rr is, The lower the conduction temperature), when the temperature of the power tube or the temperature inside the device exceeds the allowable value, the thermal thyristor is switched on and the LED is lighting to give an alarm. If cooperate with photoelectric coupler which can make whole machine alarm circuit operation, protecting switch power supply.  The circuit can also be designed as shown in Fig. 5 (b) to protect the power transistor from overheating. The base current of the switching transister is bypassed by the TT201 of the N type control gate thermal thyristor, and the switch tube is cut off, also the collector current is cut off, and the overheating is prevented. IV Conclusion This blog mainly discusses various protection methods of internal devices in DC switching power supply, and introduces some concrete circuits. For a given DC switching power supply, it is very important for the security and reliability of the power supply device whether the protection circuit is perfect and set up to work necessarily. Because the protection scheme and circuit structure of switching power supply are diverse, reasonable protection scheme and circuit structure should be chosen for specific power supply devices. In practical application, several protection methods are usually used to form a perfect protection system to ensure the normal operation of DC switching power supply.   FAQ   1. What is the purpose of circuit protection? The basic goals of circuit protection are to 1) localize and isolate the condition or fault and 2) prevent and minimize any unnecessary power loss. There are several types of abnormal conditions that may occur throughout a building's life, in which an electrical system must be designed to correct or overcome.   2. What protective devices are used in circuits? Fuses, MCBs, RCDs, and RCBOs are all devices used to protect users and equipment from fault conditions in an electrical circuit by isolating the electrical supply.   3. How do you protect a circuit design? The most basic device is a fuse, a type of low resistance resistor that acts as a sacrificial device to provide over current protection, of either the load or source circuit. A fuse protects the circuit, but once it's utilized, it's kaput.   4. What are the two main circuit protection devices? The two types of circuit protection devices discussed in this chapter are fuses and circuit breakers. A fuse is the simplest circuit protection device. It derives its name from the Latin word "fusus," meaning "to melt." Fuses have been used almost from the beginning of the use of electricity.   5. What is a DC switching power supply? A Switching DC power supply (also known as switch mode power supply) regulates the output voltage through a process called pulse width modulation (PWM). The PWM process generates some high frequency noise, but enables the switching power supplies to be built with very high power efficiency and small form factor.   6. What are the differences between linear DC power supply and switching power supply? Linear power supplies deliver DC by passing the primary AC voltage through a transformer and then filtering it to remove the AC component. Switching power supplies feature higher efficiencies, lighter weight, longer hold up times, and the ability to handle wider input voltage ranges.   7. Can I use a switching power supply to drive a DC motor? A simple unregulated analog power supply may be easier and be able to supply the large starting under load current more that the switching one. DC motors are not too fussy about the supply, and will usually run quite well on unfiltered DC.   8. Do I need a switching power supply? The switching power supply implies higher efficiency due to the high switching frequency, enabling it to use a smaller, less-costly high-frequency transformer as well as lighter, less-costly filter components. Switching power supplies contain more overall components, therefore are usually more expensive.   9. What are the 3 types of power supply? There are three subsets of regulated power supplies: linear, switched, and battery-based. Of the three basic regulated power supply designs, linear is the least complicated system, but switched and battery power have their advantages.   10. What is a switching mode power supply used for? Switched-mode power supplies are used to power a wide variety of equipment such as computers, sensitive electronics, battery-operated devices and other equipment requiring high efficiency.    

IntroductionⅠ What is a Wireless Transmitter?Ⅱ How to Make a Transmitter and Receiver Ⅲ Wireless Transmitter vs Wireless Receiver    3.1 Wireless Transmitter    3.2 Wireless Receiver    3.3 What are Optical Transmitters and Receivers?    3.4 How do You Use a Wireless Transmitter? Ⅳ Transmitter Specifications Ⅴ The Types of Transmitter Based on Modulation Scheme and Conversion Technique Employed    5.1 AM Transmitter    5.2 FM Transmitter    5.3 SSB Transmitter    5.4 Direct Conversion Transmitter    5.5 Super Heterodyne TransmitterⅥ Smart Wireless Transmitters    6.1 What are Smart Transmitters?    6.2 What are the Main Features of Smart Transmitters?Ⅶ 5 Tips to Optimize Your Sennheiser Wireless System    7.1 Don’t Cover the Antenna    7.2 Fresh Batteries are Essential    7.3 Frequency Selection is Important When Using Multiple Systems    7.4 Maintain Line of Sight between Components    7.5 Keep Transmitters and Receivers as Close as PossibleⅧ Answers to 6 Questions about the Wireless TransmitterIntroduction A wireless transmitter is a telecommunications device that generates radio waves in order to broadcast or transfer data via an antenna.This article on the transmitter specs, usage, and other parts of a full introduction will allow you to have a more detailed grasp of the wireless transmitter.Ⅰ What is a Wireless Transmitter?A wireless transmitter and associated receiver are required for devices that communicate data without the use of cables. The transmitter converts the audio signal to a radio signal and broadcasts it via an antenna as a radio wave. The antenna may protrude from the transmitter's bottom or be hidden within the transmitter. Government rules regulate the strength of radio transmission. Depending on the conditions and signal quality, the signal can successfully go up to 1,000 feet. There are two types of transmitters available. A "body-pack" or "belt-pack" transmitter, for example, is a compact box the size of a deck of cards (or smaller in some cases). The transmitter is worn on the body or clipped to the user's belt. A body-pack transmitter is commonly hooked to a guitar strap or attached directly to an instrument such as a trumpet or saxophone for instrument applications. The transmitter is incorporated into the handle of a portable wireless microphone, resulting in a wireless microphone that is just slightly larger than a normal wired microphone. For handheld wireless microphones, a range of microphone elements or "heads" are usually offered. A battery (typically a 9-volt alkaline type) is required to run all wireless transmitters.Figure-1 A wireless routerA router with an integrated wireless transmitter and receiver is included in the home or office wireless local area network (WLAN). Most routers also include a modem, allowing a single, high-speed Internet account to be shared by all connected computers. Instead of using Ethernet cables to connect the computers, each has a wireless network card (or wireless adapter) that has its own transmitter and receiver on board. Now, for instance, an individual computer can send a data request to the router, and the router can receive the request, forward it to the appropriate party, and then send the return response.Ⅱ How to Make a Transmitter and ReceiverThe Video Shows: How to make a transmitter and receiveMake your very own transmitter and receiver! Ⅲ Wireless Transmitter vs Wireless Receiver3.1 Wireless TransmitterThe radio's transmitter is powered by an alternating current flowing through a conductor (in this case an antenna). The alternating current changes direction very quickly, frequently millions or billions of times per second. The energy contained in such a fastly alternating current can be converted into Electromagnetic (EM) radiation. Electrons flowing as current produce electromagnetic radiation in the form of photons (energy packets).The resulting waves are sinusoidal, but their amplitude and frequency can be altered through modulation.3.2 Wireless ReceiverReceivers operate in the inverse of how transmitters do.The incident radio waves generate a tiny alternating current in the receiver's antenna (the photons impart their energy onto the electrons in the wire, resulting in the current). An alternating current is generated because EM waves oscillate). This alternating current signal is routed to the receiver's input.It's vital to recognize that when you tune a radio, you're selecting a frequency to listen to. To get the clearest signal, set your radio to the circuit's resonant frequency.' This is determined by the components used.3.3 What are Optical Transmitters and Receivers?The optical fiber communication system consists primarily of a transmitter and receiver, with the transmitter located on one end of a fiber cable and the receiver located on the other end of the cable. The majority of systems make use of a transceiver, which is a module that includes both a transmitter and a receiver. The transmitter receives an electrical signal and converts it to an optical signal using an LED or laser diode.Figure-2 Fiber-optic-data-linkA connector connects the light signal from the transmitter end to the fiber cable, which is then broadcasted through the cable. The light signal from the fiber end can be connected to a receiver, and wherever a detector converts the light signal to an electrical signal, it is conditioned appropriately for use by the receiving equipment.3.4 How do You Use a Wireless Transmitter?An electromagnetic disturbance is a radio wave. It spreads out in the same way that ripples in water do.First, the current flows through a wire. The wire is then surrounded by an electromagnetic field.This can be used by transmitters. They can send a pulse of electricity through a copper antenna.Furthermore, one end of the antenna will be grounded. This will restrict the signal to a single pulse.Metal effectively traps any radio waves that come into contact with it because it is a conductor of both electricity and magnetism. As a result, large metal objects in the home, such as a refrigerator, will interfere with the Wi-Fi signal. The radio waves will then emit in a regular pattern, much like ripples. The frequency of the emission will be measured in hertz (Hz).Transmitters create a carrier frequency, which is then mixed with the data signal and broadcast. This signal will be received by the receiver, which will then divide the two frequencies into their individual portions.Ⅳ Transmitter Specifications1DC coupled LEDs are used.2A serial port is Max232 IC Driver. 3The wavelength of the source is 660nm. 4The data rate is 1 Mbps.5The highest input voltage is +5V.6The maximum supply current is 100 mA. 7The maximum input voltage is +5V.8The supply voltage is +15V DC.9The LED driver is on board IC Driver.10The interface connectors are 2mm sockets. 11The type of input signal is digital data.  Ⅴ The Types of Transmitter Based on Modulation Scheme and Conversion Technique Employed The following are the different types of transmitters based on the modulation scheme and conversion technique used.5.1 AM TransmitterFigure-3 Typical block diagram of AM transmitter systemThe frequency range of an AM radio system is 540 to 1700kHz, with an IF of around 455 kHz. The frequencies are separated by 10 kHz.To convert audio information into an AM modulated signal, an AM transmitter employs amplitude modulation. AM modulation employs audio as the modulating signal and a high-frequency signal as the carrier. To achieve AM modulated output, the amplitude of the carrier signal is varied by the amplitude of the modulating audio signal.5.2 FM Transmitter          Figure-4    FM transmitter system block diagramFM radio systems operate in the frequency range of 88 to 108 MHz, with an IF of approximately 10.7 MHz. To convert audio information into an FM modulated signal, an FM transmitter employs frequency modulation. FM modulation makes use of audio as the modulating signal (Fm) and a high-frequency signal as the carrier. To achieve FM modulated output, the frequency of the carrier signal (Fc) is varied in accordance with the amplitude of the modulating audio signal.5.3 SSB Transmitter Figure-5 SSB transmitter block diagramThe upper and lower sidebands are transmitted by the AM transmitter. The upper band represents the sum of Fc and Fm, while the lower band represents the difference between Fc and Fm. A single-sideband (either upper or lower) is transmitted by an SSB transmitter, not both. In comparison to an AM transmitter, an SSB transmitter saves bandwidth and power.5.4 Direct Conversion TransmitterLet's take a look at how a direct conversion transmitter works. The signal constellation produced by this transmitter type is known as QPSK, which stands for Quadrature Phase Shift Keying.The first bit of digital data to be transmitted is divided into I and Q signals.The I and Q signals are processed by DACs.Low pass filtering is used to feed the output of DACs to mixers.The architecture employs LO (local oscillator). Before the mixing process, the LO signal is phase-shifted by 90 degrees to one of the mixers.The mixed I and Q components are added together to produce a QPSK modulated signal.Before transmission into the air, the QPSK modulated signal is amplified using a PA (Power Amplifier).Figure-6 Direct conversion transmitter5.5 Super Heterodyne TransmitterFigure-7 Superheterodyne-transmitterAfter obtaining a modulated signal via direct conversion transmitter, this architecture employs one more mixing component. The signal is bandpass filtered both before and after mixing. This necessitates the inclusion of one more LO (Local Oscillator) in the design. This type, like other transmitter systems, employs PA (Power Amplification) prior to transmission. With the help of gain control, AGC is used to vary the amplitude of the output signal. AGC stands for Automatic Gain Control.Ⅵ Smart Wireless Transmitters6.1 What are Smart Transmitters?Smart transmitters are controlled by a microprocessor. They also include an in-built sensor. The sensor enables a transmitter to filter the surrounding atmosphere. Furthermore, the transmitters can store data in memory. You can program transmitters to retain a default setting using memory storage.6.2 What are the Main Features of Smart Wireless Transmitters?The following are the key features of OMNI's smart wireless transmitters:Multiple sensors can be added for varying measurement changes.The transmitter is then adjusted to produce linear results.The transmitters are self-calibration capable.The transmitters can self-diagnose. They are capable of detecting faults and maintenance alerts.Ⅶ 5 Tips to Optimize Your Sennheiser Wireless SystemFor years, Sweetwater has configured and used large-scale Sennheiser wireless microphone systems. There are some simple steps you can take to get the most out of your Sennheiser wireless system in terms of channel count, range, and sound quality.7.1 Don’t Cover the AntennaThe antenna on a transmitter should never be covered for optimal performance. When using a handheld microphone, take care not to cover the antenna with your hand. If you don't see an antenna on your microphone, it's most likely hidden inside the last few inches of its body. Hold the microphone closer to its head/capsule to avoid covering it with your hand as you pick it up.Figure-8 Don't cover the antennaWhen wearing a belt pack with an external antenna, make sure the antenna isn't wadded up or bent. This is not only bad for the antenna (bending a wire enough times will cause it to break), but it also severely reduces its transmission. With a wadded-up antenna, you'll get limited range and more dropouts.7.2 Fresh Batteries are EssentialFigure-9 BatterySignal strength and operational range decrease when the transmitter's battery expires, so even if the battery isn't fully dead, it's better to change it at the start of every performance, event, or service.7.3 Frequency Selection is Important When Using Multiple SystemsFigure-10 Frequency SelectionTo avoid interfering with each other, the frequencies of numerous wireless systems must be properly synchronized. It's not always enough to have distinct frequencies. Using wireless systems from the same manufacturer and series is usually the best way to do this — Sennheiser's wireless systems automatically use frequencies that are already pre-coordinated to avoid interference. Consult an expert if you're integrating systems from various manufacturers or series.7.4 Maintain Line of Sight between ComponentsImproper antenna installation is the most prevalent cause of signal losses. Between the antennas and the transmitters, there should always be a clear line of sight. If this isn't possible in your rack, the antennas should be put distant from the receivers, perhaps on a wall, on a balcony rail, from the ceiling, or somewhere else where line-of-sight placement is possible.Figure-11 Maintain line of sight between componentsKeep in mind that the human body is a great RF energy absorber. Your wireless transmitter is unlikely to have enough "oomph" to carry an entire audience of people on their feet. If your antennae are in the rear of the room, the pastor's back, which requires the signal to pass through his body on its way to the receiver, may not be the best place for the belt pack transmitter.7.5 Keep Transmitters and Receivers as Close as PossibleIf you're having trouble getting clear reception, consider placing the receivers closer to the stage to shorten the distance between the transmitters and receivers. If that isn't possible, consider moving the antennae closer together by mounting them remotely. If you need to run long antenna cables, don't skimp on quality to save money — obtain the lowest-loss cable you can find. It is suggested that you use RG-8. If the cable line is longer than 25 feet, an antenna booster may be required, and it's time to contact a professional.Ⅷ Answers to 6 Questions about the Wireless Transmitter1. What is a transmitter in a wireless system?A wireless system consists of two main components: a transmitter, and a receiver. The transmitter handles the conversion of the audio signal into a radio signal and broadcasts it as a radio wave via an antenna. The antenna may stick out from the bottom of the transmitter or it may be concealed inside.2. How do I connect Bluetooth kit to FM transmitter?Simply turn on the Bluetooth on your cellphone. Or whichever device you plan on using. And search for the t-ten. And just connect the t10 and and just like that is paired.3. Can any transmitter work with any receiver?You can use a transmitter with any receiver. BUT you have to have a way of changing the antenna when you transmit. There are antenna relays for this purpose that will automatically make the change for you. The power of the transmitter would quickly destroy your receiver.4. What are the main features of transmitter?What are the main features of a transmitter? Explanation: 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. Is transmitter is same as sender?What's the difference between sender and transmitter here. Many times both terms are used for the same thing. Could it be here "Sender und Sendegeraet"? The HFN values in the sender and the transmitter are different,i.e. the HFN synchronization between the sender and receiver is lost.6. What is perfect transmitter?The important feature of the transmitter is extremely fast current, turn-off time, less than 1 μs for the shallowest depth, while the current after the ramp time is practically absent. douwdek0 and 6 more users found this answer helpful. 

This comprehensive article introduces crystal oscillators in detail, covering what this component is, how it works, the various types of crystal oscillators available, and how to select the most suitable crystal oscillator for your project.I What is a Crystal Oscillator?This video explains the working and design principles of crystal oscillators, providing valuable insights for students and engineers in understanding the operational mechanisms and design considerations.A crystal oscillator is a type of electronic oscillator that utilizes the mechanical resonance of a vibrating crystal made from piezoelectric material to generate an electrical signal with a precise frequency. Typically, a wafer is cut from a quartz crystal at a specific orientation angle and combined with integrated circuits to form an oscillating circuit within a package.As mentioned above, the resonator plate can be cut from the source crystal at different angles. The cutting method significantly influences the crystal's aging characteristics, frequency stability, thermal properties, and other parameters. Most cuts are made for bulk acoustic wave (BAW) operation, while surface acoustic wave (SAW) devices are employed for higher frequencies.2025 Update: Modern crystal oscillators now commonly operate at frequencies up to several GHz, with advanced MEMS-based oscillators becoming increasingly popular for their improved shock resistance and faster startup times.Crystal Cut Types and SpecificationsCutFrequency RangeModeAnglesDescriptionAT0.5–300MHzthickness shear (c-mode, slow quasi-shear)35°15', 0° (<25 MHz)35°18', 0°(>10 MHz)The most common cut. The plate contains the crystal's x axis and is inclined by 35°15' from the z (optic) axis. The frequency-temperature curve is sine-shaped with inflection point around 25–35°C. Has frequency constant 1.661MHz·mm.SC0.5–200MHzthickness shear35°15', 21°54'A double-rotated cut (35°15' and 21°54') for oven-stabilized oscillators with superior temperature stability.BT0.5–200MHzthickness shear (b-mode, fast quasi-shear)−49°8', 0°A special cut similar to AT cut with different temperature characteristics.ITVariousthickness shearOptimized anglesA double-rotated cut with improved characteristics for oven-stabilized oscillators.XY (tuning fork)3–85kHzlength-width flexureStandard orientationSmaller than other low-frequency cuts, less expensive, has low impedance and low Co/C1 ratio. Chief application is the 32.768 kHz RTC crystal.Crystal Oscillator Key Features:High Stability: Crystal oscillators are used in applications requiring very stable frequency references.Superior Performance: Unlike LC and RC oscillators, crystal oscillator frequency changes minimally with temperature, supply voltage, or component value variations.Excellent Selectivity: Provides very good selectivity due to high Q-factor (Quality Factor).Working Principle of Crystal Oscillator:The crystal oscillator operates on the principle of the inverse piezoelectric effect. When an alternating voltage is applied to a properly cut and mounted quartz crystal, it produces mechanical vibrations at its resonant frequency.Equivalent Circuit of Crystal:The crystal can be represented as an RLC circuit in its electrical equivalent. It has two resonant frequencies:1) Series Resonant Frequency (fs)2) Parallel Resonant Frequency (fp)The RLC circuit provides frequency selectivity for oscillation, and when combined with an amplifier, creates a complete oscillator circuit.II Crystal Oscillator Operational PrincipleA crystal is a solid material consisting of atoms, molecules, or ions arranged in a regularly ordered, repeating pattern extending in all three spatial dimensions.Any object made of elastic material can potentially serve as a resonator with appropriate transducers, as all objects have natural resonant frequencies. For example, steel was often used in mechanical filters before quartz became prevalent due to its elasticity and high speed of sound propagation.When a quartz crystal is properly cut and mounted, it can be made to deform in an electric field by applying voltage to electrodes. This property is known as the piezoelectric effect. When alternating voltage is applied, the crystal produces mechanical vibrations, which in turn generate an alternating electric field.The quartz crystal oscillator can be electrically modeled as a two-terminal network with a capacitor and resistor in parallel, plus a capacitor in series. This network has two resonance points: the lower frequency (series resonance) and the higher frequency (parallel resonance).Due to the crystal's inherent characteristics, these two frequencies are very close. Within this narrow frequency range, the crystal oscillator behaves like an inductor, forming a parallel resonant circuit when appropriate capacitors are connected.Important Note: Load capacitance is a critical parameter. Selecting a parallel capacitor matching the crystal's load capacitance specification ensures operation at the nominal resonant frequency.Key Performance Parameters:(1) Total Frequency Tolerance: The maximum frequency deviation from the nominal frequency caused by all specified operating and non-operating parameters within a specified time period.(2) Frequency Temperature Stability: The maximum allowable frequency deviation over a specified temperature range under nominal power supply and load conditions.fT = ±(fmax-fmin)/(fmax+fmin)fTref = ±max[|(fmax-fref)/fref|，|(fmin-fref)/fref|](3) Frequency Aging Rate: The relationship between oscillator frequency and time under constant ambient conditions, typically specified as ±10ppb/day after 72 hours of operation.(4) Phase Noise: The ratio of power density in phase-modulated sidebands to carrier power at a specified offset frequency from the carrier.III Crystal Oscillator ParametersFrequency Accuracy: The maximum allowable deviation between the oscillator frequency and its nominal value under specified conditions, expressed as (fmax-fmin)/f0.Temperature Stability: The allowable frequency variation over the specified temperature range, calculated as (fmax-fmin)/(fmax+fmin).Frequency Tuning Range: The range of output frequencies achievable by adjusting variable elements in the crystal oscillator circuit.Voltage-Controlled Characteristics: For VCXOs, this includes:FM Deviation: Output frequency difference when control voltage varies from maximum to minimumFM Sensitivity: Frequency change per unit control voltage changeFM Linearity: Measure of linearity compared to ideal straight-line responseLoad Characteristics: Maximum frequency deviation due to load impedance variations within specified ranges.Supply Voltage Characteristics: Maximum frequency deviation due to supply voltage variations within specified ranges.Spurious Signals: Power ratio of discrete spectral components to the main frequency, excluding harmonics, expressed in dBc.Harmonics: Ratio of harmonic component power to carrier power, expressed in dBc.Frequency Aging: Systematic frequency drift over time due to component aging, particularly the quartz resonator.Daily Stability: Frequency variation measured over 24 hours after specified warm-up time.Startup Characteristics: Maximum frequency change within specified warm-up time, expressed as V = (fmax-fmin)/f0.Phase Noise: Frequency domain representation of rapid, short-term, random phase fluctuations caused by time domain instabilities.IV. Crystal Oscillator Frequency Stability & Input/OutputFrequency StabilityFrequency stability over operating temperature is one of the primary characteristics determining oscillator cost. Higher stability requirements or wider temperature ranges result in higher device costs.Crystal aging is a significant factor in long-term frequency stability. The aging rate follows a logarithmic curve and is most pronounced during the first year of operation. For applications requiring 10+ year operation, the aging rate is approximately three times that of the first year.2025 Update: Modern crystal oscillators now achieve aging rates as low as ±0.1 ppb/day for high-end OCXO units, and MEMS oscillators offer improved aging characteristics compared to traditional quartz devices.Other factors affecting frequency stability include supply voltage variations, load changes, phase noise, jitter, and electromagnetic interference (EMI). For industrial applications, vibration and shock specifications are critical, while aerospace applications require tolerance specifications for pressure changes and radiation exposure.Output TypesCrystal oscillators are available with various output types compatible with different logic families:HCMOS/TTL: Most common for digital applicationsACMOS: Low power applicationsECL: High-speed applicationsLVDS: High-speed differential signalingHCSL: High-speed current steering logicSine Wave: Analog applications requiring pure sinusoidal outputCritical specifications include symmetry (typically 45%-55%), rise/fall times (often <5ns for high-speed applications), and logic levels. Many DSP and communication chipsets require strict symmetry and fast edge rates.Phase Noise and JitterPhase noise, measured in the frequency domain, represents true short-term stability. It's typically measured from 1Hz to 1MHz offset from the carrier frequency. Crystal oscillators using fundamental or harmonic modes provide the best phase noise performance, while PLL-based synthesized oscillators generally exhibit poorer phase noise characteristics.Jitter, related to phase noise but measured in the time domain, is specified in picoseconds (RMS or peak-to-peak). Applications such as communication networks, wireless data transmission, ATM, and SONET require careful attention to both characteristics.V Crystal Oscillator ApplicationsCrystal oscillators serve as precision clock sources in microcontroller systems and can be categorized into two main types:Mechanical resonance devices: Crystal oscillators and ceramic resonators (suitable for Pierce oscillator configurations)RC oscillators: Lower cost but less accurate alternativesCrystal oscillators and ceramic resonators provide high initial accuracy and low temperature coefficients. RC oscillators offer quick startup and lower cost but typically achieve only 5%-50% accuracy over temperature and supply voltage ranges.Environmental ConsiderationsEnvironmental factors affecting oscillator performance include:Electromagnetic Interference (EMI)Mechanical vibration and shockHumidityTemperature variationsSupply voltage fluctuationsThese factors can cause frequency instability and, in severe cases, oscillator failure. Oscillator modules help mitigate many of these issues by providing complete, tested solutions with specified environmental tolerances.Power Consumption ConsiderationsPower consumption varies significantly by oscillator type:Discrete crystal circuits: 1-5mA typicalCrystal oscillator modules: 10-60mA typicalMEMS oscillators: 1-50mA depending on frequency and featuresUltra-low power oscillators: <1mA for battery-powered applicationsCommon ApplicationsGeneral oscillating circuits for frequency generationDigital clock generation for processors and microcontrollersMicroprocessor timing referencesConsumer electronics (TV, VCR, DVD players)Timekeeping applications (watches, clocks, RTCs)Communication systems (cellular, WiFi, Bluetooth)Test and measurement equipmentAutomotive electronicsIndustrial control systemsVI Crystal Oscillator TypesCrystal oscillators are classified into several categories based on their design and application requirements:By Temperature Compensation Method:TCXO: Temperature-Compensated Crystal OscillatorVCXO: Voltage-Controlled Crystal OscillatorOCXO: Oven-Controlled Crystal OscillatorDCXO: Digitally Compensated Crystal OscillatorMCXO: Microcomputer-Compensated Crystal OscillatorBy Circuit Configuration:Passive Crystal Oscillators: Require external oscillator circuitActive Crystal Oscillators: Complete oscillator with built-in amplificationBy Package Type:Metal Can: Traditional hermetic sealingCeramic: Good thermal propertiesPlastic: Cost-effective for commercial applicationsSMD: Surface mount for automated assemblyCommon Types and AbbreviationsAbbreviationFull NameTypical StabilityTCXOTemperature-Compensated Crystal Oscillator±0.1 to ±2.5 ppmVCXOVoltage-Controlled Crystal Oscillator±25 to ±100 ppmOCXOOven-Controlled Crystal Oscillator±0.001 to ±0.1 ppmDCXODigitally Compensated Crystal Oscillator±0.1 to ±1 ppmMCXOMicrocomputer-Compensated Crystal Oscillator±0.05 to ±0.5 ppmGPSDOGPS Disciplined Oscillator±0.001 ppmMEMSMicro-Electro-Mechanical Systems Oscillator±20 to ±100 ppm2025 Update: MEMS oscillators have gained significant market share due to their superior shock/vibration resistance, faster startup times, and programmability. They're increasingly used in automotive and IoT applications.Active vs. Passive Crystal OscillatorsPassive Crystal Oscillators:Require external oscillator circuit in the CPU/MCUTwo-pin, non-polar componentSignal level determined by the driving circuitCan work with various supply voltagesLower costRequire careful PCB layout and component matchingActive Crystal Oscillators:Complete oscillator with built-in amplificationFour-pin device with power supply connectionsFixed output signal levelBetter signal quality and stabilitySimpler connection (typically requires only power supply filtering)Higher cost but more reliable operationAvailable in various output formats (CMOS, TTL, LVDS, etc.)VII Crystal Oscillator Selection GuideSelecting the appropriate crystal oscillator requires careful consideration of application requirements and environmental conditions.Selection Criteria by Stability Requirements:±100 ppm or less: Standard XO or VCXO±5 to ±25 ppm: TCXO±0.5 to ±5 ppm: High-grade TCXO or ATCXO±0.1 to ±0.5 ppm: MCXO or DCXO±0.01 to ±0.1 ppm: OCXOBetter than ±0.01 ppm: GPSDO or atomic referenceApplication-Specific Considerations:Communication Systems:Cellular base stations: OCXO or high-grade TCXOMobile devices: TCXO with voltage controlWiFi/Bluetooth: Standard TCXOSatellite communication: OCXO with GPS discipliningComputing and Digital Systems:Microprocessors: Standard XO or TCXOHigh-speed processors: Low-jitter TCXO or MEMSReal-time clocks: 32.768 kHz tuning fork crystalsNetwork equipment: Low-jitter TCXO or OCXOTest and Measurement:Frequency counters: OCXOSignal generators: OCXO with low phase noiseOscilloscopes: Low-jitter TCXOSpectrum analyzers: Ultra-low phase noise OCXOEnvironmental Considerations:Temperature Range:Commercial (0°C to +70°C): Standard gradesIndustrial (-40°C to +85°C): Industrial gradesMilitary (-55°C to +125°C): Military-grade devicesAutomotive (-40°C to +125°C): AEC-Q100 qualifiedMechanical Environment:High vibration: MEMS oscillators or ruggedized crystalsShock resistance: MEMS or specially mounted crystalsSize constraints: Ultra-miniature packages (1.6×1.2mm or smaller)Power Consumption Optimization:Battery-powered devices: Ultra-low power TCXO or MEMSAlways-on applications: Low standby current oscillatorsPortable devices: Programmable MEMS with power-down modesPackage Selection:Through-hole: Traditional DIP packages for prototypingSurface mount: Various sizes from 7×5mm to 1.6×1.2mmUltra-miniature: Wafer-level chip scale packages (WLCSP)Development Trends (2025):Miniaturization: Continued reduction in package sizesIntegration: Multi-frequency and programmable outputsMEMS adoption: Replacing quartz in many applicationsIoT optimization: Ultra-low power and wireless-friendly designs5G/6G requirements: Ultra-low jitter and phase noiseAutomotive growth: AEC-Q100 qualified devices for ADAS and autonomous vehiclesTesting and Quality Assurance:Common crystal oscillator failure modes include:Internal leakage: Contamination or seal failureOpen circuit: Wire bond or connection failureFrequency drift: Aging or temperature effectsExternal component failure: Load capacitor issuesTesting Methods:1) Resistance Measurement: Use multimeter on high resistance range. Normal crystals should show infinite resistance in both directions. Any finite resistance indicates leakage or breakdown.2) Capacitance Measurement: Measure crystal capacitance using LCR meter or digital multimeter with capacitance function. Compare with expected values for the crystal type.3) Oscillation Test: Build simple test oscillator circuit to verify crystal functionality. Successful oscillation indicates good crystal condition.4) Frequency Accuracy Test: Use frequency counter to verify output frequency matches specification within tolerance.5) Temperature Testing: Verify frequency stability over specified temperature range.Recent Industry DevelopmentsIndustry Update: Leading manufacturers continue to push the boundaries of crystal oscillator performance. Recent developments include:Ultra-low jitter differential output oscillators achieving 65 fs phase jitterHigh-frequency fundamental (HFF) AT-cut crystals using advanced QMEMS processesImproved reliability compared to traditional 3rd overtone crystalsSupport for multiple differential output formats (HCSL, LVDS) in compact packagesEnhanced temperature stability for 5G and high-speed networking applicationsThe SG7050EBN series represents the latest advancement in differential-output crystal oscillators, operating from 100 MHz to 175 MHz with exceptional 65 fs phase jitter performance. This makes it suitable for 10-, 40-, and 100-Gigabit Ethernet applications in datacenters and telecommunications infrastructure.Frequently Asked Questions (FAQ)1. What is a crystal oscillator used for?A crystal oscillator is an electronic circuit that uses the mechanical resonance of a vibrating piezoelectric crystal to create an electrical signal with a precise frequency. It's used for timing references, clock generation, frequency synthesis, and signal processing applications.2. What are the advantages of crystal oscillators?Crystal oscillators offer very high frequency stability, precise and stable frequency generation, high Q-factor, low frequency drift with temperature and parameter changes, and excellent long-term stability compared to other oscillator types.3. What is the difference between a crystal and an oscillator?A crystal is the piezoelectric resonator element itself, while an oscillator is the complete circuit including the crystal, amplifier, and supporting components. The crystal provides the frequency reference, while the oscillator circuit sustains oscillation.4. How does a crystal oscillator work?The crystal oscillator circuit sustains oscillation by taking a voltage signal from the quartz resonator, amplifying it, and feeding it back to the resonator. The rate of expansion and contraction of the quartz determines the resonant frequency, based on the crystal's cut and size.5. What is the principle of oscillation?Electronic oscillators operate on the principle of positive feedback: a sensitive amplifier's output is fed back to the input in phase, causing the signal to regenerate and sustain itself through continuous positive feedback.6. What is the main feature of crystal oscillators?The most important feature is frequency stability - the ability to provide a constant frequency output under varying load conditions, temperature changes, and aging effects over long periods.7. Why is quartz crystal commonly used?Quartz is preferred due to its availability, mechanical strength, chemical stability, low cost, excellent piezoelectric properties, and predictable temperature characteristics. It also has a high Q-factor and good aging characteristics.8. Why are crystal oscillators more stable?Crystal oscillators are more stable because the mechanical resonance of quartz is highly stable and only minimally influenced by external factors like temperature, voltage, or component variations, unlike LC or RC oscillators.9. How do you test a crystal oscillator?Test methods include resistance measurement (should be infinite), capacitance measurement (compare to specifications), oscillation testing (build test circuit), and frequency accuracy verification using a frequency counter.10. Why are crystals used in microcontrollers?Crystal oscillators provide the precise clock signals required for microcontroller synchronization, ensuring accurate timing for instruction execution, peripheral operations, and communication protocols.11. Do crystal oscillators have polarity?Passive crystals (2-pin) have no polarity and can be connected in either direction. Active crystal oscillators (4-pin) have specific pin assignments for power, ground, and output that must be observed.12. Do crystal oscillators fail?Yes, crystal oscillators can fail due to mechanical shock, overheating beyond the Curie temperature, contamination, aging, or electrical overstress. However, they are generally very reliable components when properly used.13. Can crystals oscillate at multiple frequencies?Yes, crystals can oscillate at overtones (odd multiples of the fundamental frequency), but these are typically weaker than the fundamental. Circuits can be designed to operate crystals at their 3rd or 5th overtones.14. Why are oscillators used in electronic systems?Oscillators convert DC power to AC signals, providing timing references, clock signals, carrier frequencies for communication, and synchronization signals essential for digital and analog electronic systems.15. Why were crystal oscillators important for radio transmitters?Crystal oscillators provided the frequency stability needed for radio transmitters to maintain their assigned frequencies, preventing interference with other stations and ensuring reliable communication. They became standard in AM radio by 1926.Reference ComponentsLatest High-Performance Crystal Oscillators:SG7050EBN 125.000000M-DJGA3 - Ultra-low jitter differential oscillatorSG7050EBN 125.000000M-CJGA3 - High-frequency networking applicationsSG7050EBN 100.000000M-CJGA3 - 100 MHz precision referenceDisclaimer: This article has been updated for 2025 to reflect current technology trends and specifications. Always consult the latest datasheets and manufacturer specifications for current product information. body { font-family: Arial, sans-serif; line-height: 1.6; margin: 0; padding: 20px; background-color: #f5f5f5; } .container { max-width: 100%; margin: 0 auto; background-color: white; padding: 20px; border-radius: 8px; box-shadow: 0 2px 10px rgba(0,0,0,0.1); } h1, h2 { color: #333; border-bottom: 2px solid #1f497d; padding-bottom: 10px; } h1 { font-size: 24px; text-align: center; } h2 { font-size: 20px; margin-top: 30px; } p { font-size: 16px; margin-bottom: 15px; text-align: justify; } img { max-width: 100%; height: auto; display: block; margin: 20px auto; border-radius: 5px; } table { width: 100%; border-collapse: collapse; margin: 20px 0; font-size: 14px; } table, th, td { border: 1px solid #ddd; } th, td { padding: 8px; text-align: left; } th { background-color: #f2f2f2; font-weight: bold; } .highlight { background-color: #e8f4fd; padding: 15px; border-left: 4px solid #1f497d; margin: 20px 0; } .formula { color: #548dd4; font-style: italic; text-align: center; margin: 10px 0; } .faq-question { color: #e36c09; font-weight: bold; margin-top: 20px; } .video-container { position: relative; width: 100%; height: 0; padding-bottom: 56.25%; margin: 20px 0; } .video-placeholder { position: absolute; top: 0; left: 0; width: 100%; height: 100%; background-color: #f0f0f0; display: flex; align-items: center; justify-content: center; border: 2px dashed #ccc; } a { color: #f60; text-decoration: none; } a:hover { text-decoration: underline; } .note { background-color: #fff3cd; border: 1px solid #ffeaa7; padding: 10px; border-radius: 5px; margin: 15px 0; } .update-badge { background-color: #28a745; color: white; padding: 3px 8px; border-radius: 12px; font-size: 12px; margin-left: 10px; } @media (max-width: 768px) { .container { padding: 15px; } h1 { font-size: 22px; } h2 { font-size: 18px; } p { font-size: 15px; } table { font-size: 12px; } th, td { padding: 6px; } }

Introduction The operational amplifier has a non-inverting input terminal and an inverting input terminal in the electronic circuit. The polarity of the input terminal and the output terminal are the same is a non-inverting amplifier, and the polarity of the input terminal and the output terminal are opposite called inverting amplifier. The inverting amplifier circuit has the function of amplifying the input signal as inverting output. Inverting Op Amp and The Concept of Virtual Ground in Op Amp Catalog Introduction Ⅰ Inverting Amplifier Basics Overview 1.1 Working Principle 1.2 Inverting Amplifier Gain Calculator 1.3 Inverting Amplifier Features 1.4 Inverting Amplifier Functions Ⅱ Inverting Amplifier Applications Ⅲ Inverting Amplifier Explain with Diagrams: NE5532 Ⅳ Inverting Amplifier Circuit Design Steps Ⅴ FAQ Ⅰ Inverting Amplifier Basics Overview 1.1 Working Principle As shown in Figure 1, the inverting amplifier circuit has the function of amplifying the input signal as inverting output. "Inverting" means that the positive and negative signs are reversed. This amplifier uses negative feedback technology, which used to return a part of the output signal to the input. In Figure, the wiring method of connecting the output Vout to the inverting input terminal (-) via R2 is negative feedback. Figure 1. Inverting Amplifier Circuit Operational amplifiers have such characteristics. When the power supply voltage is not applied to the output terminal, the non-inverting input terminal (+) and the inverting input terminal (-) are considered to have the same voltage, that is to say, it can be regarded as a virtual short circuit. Therefore, when the positive input terminal (+) is 0V, the voltage at output is also 0V.The input impedance of the operational amplifier is extremely high, and there is basically no current in the inverting input terminal (-). Therefore, when the current flows to R2, the I1 and I2 are basically equal. Based on the above conditions, using Ohm's Law for R2, we get Vout=-I1xR2. I1 is negative because I2 flows from point A where the voltage is 0V. From another point of view, when the input voltage of the inverting input terminal (-) rises, the output will be inverted and amplified greatly in the negative direction. Since the output voltage in the negative direction is connected to the inverting input terminal via R2, the voltage rise of the inverting input terminal (-) will be blocked. Both the inverting input terminal and the non-inverting input terminal voltage become 0V, and the output voltage is stable.   1.2 Inverting Amplifier Gain Calculator Calculate the gain through the relationship between the input and output in this amplifier circuit. The gain of an inverting op amp is the ratio of the feedback resistance to the input resistance, that is, the ratio of Vout to Vin, and the formula is Vout/Vin= (-I1xR2) /(I1xR1)=-R2/R1. The resulting gain is negative, indicating that the waveform is inverting.The current flowing through R1: I1=(Vi-V-)/R1...aThe current flowing through R2: I2=(V--Vout)/R2……bV-=V+=0………………cI1=I2……………………dSolve the above algebraic equations to get Vout=(-R2/R1)*Vi.This is the input and output relationship of the inverting amplifier circuit.   1.3 Inverting Amplifier Features It can reduce the input impedance or keep a certain value.It can be used as a current input type.Virtual short-circuit point is generated at a certain potential.Its positive input port is free.If the signal source impedance is low, it is easier to obtain a required S/N.The magnification is -Rf/R.   1.4 Inverting Amplifier Functions The inverting amplifier is the basic gain stage in the CMOS circuit. It adopts a common source structure, and the load can be an active load or a current source.Advantages: The potential of the two input terminals is always approximately zero (the non-inverting terminal is grounded, and the inverting terminal is virtual ground). With only differential mode signals,it has strong anti-interference ability.Disadvantages: The input impedance is very small, equal to the resistance of the series resistance from the signal to the input.   Ⅱ Inverting Amplifier Applications Figure 2. Basic Inverting Amplifier Circuit 1) As a IntegratorThe original resistor R2 of the inverting amplifier is replaced by a capacitor C2. At this time, the relationship between the input signal Vi and the output signal Vo forms an integral relationship.2) As a DifferentiatorReplace the original resistor R1 of the inverting amplifier with an electric capacitor C. At this time, the relationship between the input signal Vi and the output signal Vo is differential.3) As a AdderIf the inverting amplifier is slightly changed, the relationship between the input signal and the output signal Vo at this time, if R1 = R2 = R3 =...= Rn = Rf, it can be simplified to Vo = -(V1+V2+V3+.. .+Vn), is additive.   Ⅲ Inverting Amplifier Explain with Diagrams: NE5532 The equivalent resistance seen between the input terminal and the ground of the inverting amplifier circuit is equal to the equivalent resistance between the input terminal and the virtual ground, so the input resistance of the circuit is Ri=R. It can be seen that although the input resistance of the ideal operational amplifier is infinite, the input resistance of the inverting proportional arithmetic circuit is not large because of the parallel negative feedback introduced by the circuit. Figure 3. NE5532 Audio Amplfier Circuit In order to increase the input resistance, R must be increased. For example, when the scale factor is -50, if Ri=10kΩ, R should be 10kΩ and Rf should be 500kΩ. If Ri=100kΩ, R should be 100kΩ and Rf should be 5MΩ. In fact, when the resistance in the circuit is too large, on the one hand, due to the process, the stability of the resistance is poor and the noise is large, on the other hand, when the resistance is of the same order of magnitude as the input resistance of the integrated op amp, the proportional coefficient -Rf/R of the circuit will change greatly, and its value will not only be determined by the feedback network. Therefore, it is necessary for practical applications to use a resistor with a smaller resistance value to get a larger scale factor and a larger input resistance.Look at the following two simulations: Figure 4. Current and Voltage Measuring From above, it doesn't matter without R0, take a look at this below. Figure 5. Current and Voltage Measuring Their output is different, if the expected result is -4V. The reading value -3.608V obviously does not meet the design requirements. We now know that the resistance value of Rs in Figure 5 is orders of magnitude greater than the input resistance of the integrated operational amplifier. Next, if have R0, look at the picture below. Figure 6. Current and Voltage Measuring It can be seen from Figure 6 that after adding R0, the output of the op amp is normal. Why is this?In a TTL circuit, the transistor has a bias current, which will produce a DC voltage drop on the feedback resistor of the e pole. Although it is small, the amplifier has a high amplification factor, which affects the output accuracy greatly. A resistor in the same value as the negative terminal is connected to the positive terminal to cancel the effect of the bias current.R0 is a compensation resistor, which minimizes the bias current error to ensure the symmetry of the differential amplifier circuit of the input stage. When its value is u=0 (that is, the input terminal is grounded), the inverting input terminal is always the equivalent resistance, that is, the parallel connection of the resistance of each branch, so R0=Rs/Rf, through Rf in the circuit, induce negative feedback. According to practical experience, it is best to add a compensation resistor to improve the stability of the circuit. Of course, it can be omitted under normal circumstances.   Ⅳ Inverting Amplifier Circuit Design Steps Inverting amplifiers are several commonly used amplifier types. How to use operational amplifiers design inverting amplifier circuit? The following sharing is the detailed steps.Step 1: Determine the magnification.As shown in the figure below, the amplification factor of the inverting amplifier is (-R2/R1). Figure 7. Determine the Magnification Step 2: Determine the supply voltage.Ensure that the output voltage after the input voltage Vin is multiplied by the amplification factor (-R2/R1) will not exceed the power supply voltage. If it is not the rail-to-rail operational amplifier used, it is better to have a margin of 1~2V. Figure 8. Determine the Supply Voltage Step 3: Determine the gain bandwidth product (GBW).If you are amplifying an AC signal, you need to consider the gain bandwidth product. The calculation formula is: bandwidth of input signal × design gain, select an operational amplifier whose GBW is greater than the required one. Step 4: Check the bandwidth with the slew rate (SR).If the amplifying is a large AC signal, there may be insufficient bandwidth, and it may not be accurate enough to calculate based on the gain-bandwidth product.SR = 2*pi*f*Vp -> f = SR/(2*pi*Vp), where Vp: peak output voltage.If the calculated value f is less than the input voltage frequency, the operational amplifier is not suitable and needs to be replaced. The actual bandwidth should be the smaller of the gain bandwidth product and the slew rate. Step 5: Determine the input offset voltage.Since the offset voltage is also a DC signal, if it is to amplify the DC signal, it should be noted that the offset voltage will also be amplified by the corresponding multiple. If the accuracy is high, try to choose an operational amplifier with a small offset voltage. Step 6: Determine the resistance value.In step 1, the ratio of R1 and R2 has been determined. R1 is generally 1k~10k. A small value is prone to cause gain errors, and a larger value will increase noise (resistor thermal noise). R2 takes the resistance value corresponding to the multiple of R1.It is better to choose the chip resistor, because the parasitic parameters are small.R3=R1/R2, if R1 and R2 are connected in parallel, which are not required.   Ⅴ FAQ 1. What is the inverting amplifier?An inverting op amp is an operational amplifier circuit with an output voltage that changes in the opposite direction as the input voltage. In other words, it is out of phase by 180o。   2. What is inverting amplifier and its application?The inverting amplifier is an important circuit configuration using op-amps and it uses a negative feedback connection. An inverting amplifier, like the name suggests, inverts the input signal as wells as amplifies it.   3. How does an inverting amplifier circuit work?In an inverting amplifier circuit, the operational amplifier inverting input receives feedback from the output of the amplifier. Assuming the op-amp is ideal and applying the concept of virtual short at the input terminals of op-amp, the voltage at the inverting terminal is equal to non-inverting terminal.   4. What are the applications of inverting amplifier?op-amp inverting amplifier. Op amp summing amplifier: Based around the inverting amplifier circuit with its virtual earth summing point, this circuit is ideal for summing audio inputs. It is widely used in audio mixer and many other applications where voltages need to be summed.   5. Why is it called inverting amplifier?It is called Inverting Amplifier because the op-amp changes the phase angle of the output signal exactly 180 degrees out of phase with respect to input signal. Same as like before, we use two external resistors to create feedback circuit and make a closed loop circuit across the amplifier.   6. What are the characteristics of inverting amplifier?1) No Current Flows into the Input Terminals.2) The Differential Input Voltage is Zero as V1 = V2 = 0 (Virtual Earth)   7. What is the formula of inverting amplifier?One final point to note about the Inverting Amplifier configuration for an operational amplifier, if the two resistors are of equal value, Rin = Rƒ then the gain of the amplifier will be -1 producing a complementary form of the input voltage at its output as Vout = -Vin.   8. What are advantages and disadvantages of inverting amplifier?Advantages and Disadvantages of Inverting AmplifierIt follows the negative feedback. The gain factor of these amplifiers is very high. The output generated will be out of phase with the applied input signal. The potential values at both the inverting and the non-inverting terminals maintained at zero.   9. What are the advantages of inverting amplifier?The op amp circuit for the inverting amplifier offers many advantages including relatively low input impedance, a low output impedance and the level of gain that is required (within the limits of the op amp and the gain required from the overall circuit.   10. What is the use of inverting amplifier?The inverting amplifier is an important circuit configuration using op-amps and it uses a negative feedback connection. An inverting amplifier, like the name suggests, inverts the input signal as wells as amplifies it.   11. What is mean by inverting amplifier?An inverting amplifier takes an input signal and turns it upside down at the op amp output. When the value of the input signal is positive, the output of the inverting amplifier is negative, and vice versa. ... The amount of amplification depends on the ratio between the feedback and input resistor values.   12. How an opamp is used as inverting amplifier?Theory: An inverting amplifier using opamp is a type of amplifier using opamp where the output waveform will be phase opposite to the input waveform. The input waveform will be amplifier by the factor Av (voltage gain of the amplifier) in magnitude and its phase will be inverted.   13. What is an inverting amplifier used for?op-amp inverting amplifier. Op amp summing amplifier: Based around the inverting amplifier circuit with its virtual earth summing point, this circuit is ideal for summing audio inputs. It is widely used in audio mixer and many other applications where voltages need to be summed.   14. How does an inverting amplifier work?An inverting amplifier takes an input signal and turns it upside down at the op amp output. When the value of the input signal is positive, the output of the inverting amplifier is negative, and vice versa.   15. What is the gain of an inverting amplifier?The gain of inverting amplifier is Av= – Rf/Ri.

Introduction Linear Displacement Sensor, also called Linear Transducer or Linear Potentiometer Sensor, is a device used to monitor and measure linear position, which convert mechanical physical quantities into electrical signals. Linear potentiometer is a type of variable resistance sensor, designed to measure the displacement of a slider or wiper in a linear direction. Also known as a slider or pot, linear potentiometers produce a changing rate of resistance, dependent on the position of a slider or wiper. LVIT Linear Position Sensor Technology Catalog Introduction Ⅰ Linear Displacement Sensor Working Principle Ⅱ Linear Potentiometer Sensor Design Parameters Ⅲ Linear Transducer Applications Ⅳ Linear Displacement Sensor Types Recommendation Ⅴ Linear Potentiometer Sensor Installation Ⅵ Linear Transducer Operating Requirements Ⅶ Linear Displacement Sensor Use Matters Ⅷ FAQ Ⅰ Linear Displacement Sensor Working Principle The function of the linear displacement sensor is to convert the linear mechanical displacement into an electrical signal. In order to achieve this effect, the sensor slide rail is connected to a steady-state DC voltage, allowing a small current of microamperes to flow, and the voltage between the slide and the starting end is proportional to the length of the slide. Using the sensor as a voltage divider can minimize the requirements for the accuracy of the total resistance of the sliding rail, because the resistance change caused by the temperature change will not affect the measurement result. The linear displacement sensor is actually a sliding rheostat. Using the sensor as a voltage divider can minimize the requirements for the accuracy of the total resistance of the sliding rail, because the resistance change caused by the temperature change will not affect the measurement result. Figure 1. KTC 300mm Linear Displacement Sensor Ⅱ Linear Potentiometer Sensor Design Parameters For the general linear displacement sensor:Wear resistance life: >100X106 timesLinear accuracy error: <0.05%Repeatability error: <0.005mmMaximum moving speed: 10m/sImpact factor: IEC 68-2-29:1968 50gVibration factor: IEC 68-2-6:1982 20gMaximum allowable voltage: DC60V/5KΩ～20KΩ; DC36V/2KΩ～4KΩ; DC24V/1KΩTemperature drift coefficient: <1.5ppm/℃ Figure 2. KTR-75mm Linear Displacement Transducer Ⅲ Linear Transducer Applications 1) KTC, KTM, LS tie rod structure is a general structure, with optional pull ball universal head or universal head, can reduce the adverse effects caused by the installation of non-neutral. They are suitable for injection molding machines, textile machinery, woodworking machinery, etc.2) KPC and KPM fixed belts at both ends are hinged and sporty, suitable for swinging, and in measurement systems where the sensor body cannot be fixed, and the sensor will move with the measurement movement.3) KTF and KFM slider types are suitable for the application of the smallest installation length size. With the extension arm, it can eliminate the adverse effects of installation misalignment.4) KTR type is a miniature self-recovery rod structure, no need to tow and install.5) KPF type can also detect the internal displacement of the cavity. Figure 3. KPM Linear Displacement Sensor Ⅳ Linear Displacement Sensor Types Recommendation 🔺Tie Rod TypeUniversal drawbar conductive plastic film series, effective stroke 75mm ~ 1250mm, 4mm buffer stroke at both ends, precision 0.05%~ 0.04%FS. The surface of the shell is anodized, anti-corrosion.Built-in conductive plastic measuring unit, no temperature drift, long life, and automatic electrical grounding function. The sealing grade is IP67, DIN430650 standard plug and socket, which can be applied to most general occasions.The tie rod ball joint has 0.5mm automatic centering function, and the allowable extreme movement speed is 10m/s.🔺Sliding TypeGeneral-purpose slider conductive plastic film series, effective stroke 75mm～3000mm, 4mm buffer stroke at both ends, precision 0.05%～0.02%FS. The surface of the shell is anodized, anti-corrosion.Built-in conductive plastic measuring unit, no temperature drift, long life, and automatic electrical grounding function. The sealing level is IP54 (IP57 when installed downwards), DIN430650 standard plug and socket, which can be used in most general occasions, especially the length direction is limited, the alignment is difficult.The tie rod with the ball head has 10mm automatic correction function, and the allowable limit motion speed is 10m/s. Figure 4. KPC Linear Displacement Sensor Ⅴ Linear Potentiometer Sensor Installation 1) The installation of the linear displacement sensor should balance two ends. Do not tighten the fixing bracket screws before the limit position is determined. The linear displacement sensor fixing bracket screws can be locked after adjusting the stroke.2) The pull-ball universal head of the tie-rod displacement sensor allows a centering deviation with a radius of 1mm. Of course, the shorter the specification, the smaller the centering deviation is recommended.3) After fixing the linear displacement sensor, when retracting the tie rod, the cylindrical body of the universal ball head should be able to have gaps in the four radial directions. Or adjust the mounting position of the universal head or the mounting bracket position near the extended end.4) If there is a big misalignment when the pull rod is pulled out, adjust the mounting bracket near the end of the plug. This can be used as an auxiliary review method.5) The mounting rod of the pull ball universal head and the pull rod are allowed to tilt at an angle of 12°. However, if the centering deviation and tilt deviation are both large during installation, the stability and service life of the electronic ruler will be affected. So further adjustment is required.6) The slider electronic ruler can reduce the workload of adjusting the neutrality, but the auxiliary extension rod cannot be cancelled. Because the stability and service life due to the poor neutralization will occur, and even damage the sensor.7) After all adjustments are made, tighten the mounting screws to make the grounding resistance less than 1. Measure the resistance between the cover screw of the potentiometer sensor and the mounting bracket with a multimeter in the 200 block.8) When using a four-wire system or wiring with a shielded wire, the grounding end of the linear potentiometer should be connected, and the fourth end or shielding wire should be grounded at the end of the electric control box correctly. Figure 5. KTM Linear Displacement Sensor Ⅵ Linear Transducer Operating Requirements 🔺The supply voltage should be stable.Industrial power supply requires ±0.1% stability. For example, the reference voltage is 10V, and the fluctuation of ±0.01V is allowed under the fluctuating voltage. Otherwise, it will cause the displayed trap to fluctuate. 🔺Prevent electrostatic interference.Electrostatic interference and FM interference can easily make the digital display of the linear displacement sensor jump. Separate the strong current line of the equipment from the signal line of sensor in a wire duct. The potentiometer should use a grounding support, and its shell (the resistance between the end cover screw and the support should be less than 1Ω) must be well grounded. The signal line should be shielded and well grounded where at one end of the electrical box.In the case of electrostatic interference, the voltage measurement of the general multimeter is normal, but it shows the digital beating, even the phenomenon is the same when the high-frequency device is interfered. To verify whether it is electrostatic interference, use a power cord to short-circuit the cover screw of the sensor with a certain point of metal on the machine. However, it is difficult to eliminate high-frequency interference by the above-mentioned methods, which occurs frequently in robots and inverters. Stopping the robot or the inverter power saver can test it. 🔺WiringLines "1" and "3" are power lines, and "2" is the output line. Once the above line is connected wrongly, there will be large linear errors, resulting in poor control accuracy, and display bounce easily. 🔺The power supply capacity should be sufficient.If the power supply capacity is too small, the following situations are likely to occur: the mold clamping movement will cause the display of the glue injection ruler to jump, or the melt movement will cause the display of the mold clamping potentiometer sensor to fluctuate. Especially when the power supply of solenoid valve drive power supply is combined with the sensor, the above-mentioned situation is prone to occur. In severe cases, the voltage fluctuation can be measured with the voltage file of a multimeter. If the problem cannot be solved, even if the electrostatic interference and high-frequency interference are eliminated, the neutrality is also bad. At this time, you can check the power supply efficiency. 🔺Installation angleThe angle tolerance is ±12°, and the parallelism tolerance is ±0.5mm. If both are too large, it will cause the display number to jump. In this case, the angle and parallelism must be adjusted. 🔺Prevent short circuit.During the working process of the displacement sensor, the data is regularly displayed at a certain point or no data. In this case, it is necessary to check whether the connection line insulation is damaged and the ground short circuit caused by regular contact with the machine's metal casing. 🔺Avoid aging.For the linear displacement sensor that has been used for a long time, the seal is aging, there may be a lot of impurities, such as oil and water mixture, which affect the contact resistance of the brush, and cause the display number. It can be considered as the early damage of sensor. Figure 6. KTF Linear Displacement Sensor Ⅶ Linear Displacement Sensor Use Matters 1) If the potentiometer sensor has been used for a long time, and the seal has been aging, there are a lot of impurities mixed in, and the water mixture and oil will seriously affect the contact resistance of the brush, which will cause the displayed number to jump continuously. At this time, it can be said that the electronic ruler of the linear displacement sensor has been damaged and needs to be replaced.2) If the capacity of the power supply is small, there will be many situations. Therefore, the power supply should have sufficient capacity. Because insufficient capacity will cause the following situation: The movement of the melt will change the display of the sensor to cause the fluctuations,  resulting in a large error in the measurement result.If the driving power of the solenoid valve and the power supply of the linear displacement sensor are at the same time, the above situation is more likely to occur. In serious cases, the voltage range of the multimeter can even measure the relevant fluctuations of the voltage. If the situation is not caused by high-frequency interference, electrostatic interference, or insufficient neutrality, then it may be caused by the small power supply.3) FM interference and electrostatic interference may cause the digital scale of the linear displacement sensor to jump. The signal line of the sensor and the strong current line of the equipment should be separated from the wire duct. Use the grounding support to have good contact with the ground. The signal wire needs to use a shielded wire, and a section of the electrical box should be grounded to the shielded wire.If there is high-frequency interference, the voltage measurement with a multimeter will usually display abnormally. When there is electrostatic interference, the situation is the same as that of high-frequency interference. To prove whether it is electrostatic interference, you can use a power cord to short-circuit the cover screw of the sensor with some metal on the machine. As long as it is short-circuited, the e-interference will be eliminated immediately. However, if you want to eliminate high-frequency interference, it is difficult to use the above method. Frequency-conversion power savers and robots often have high-frequency interference, so you can try to stop them to verify the interference.4) The power supply voltage must be stable. The industrial voltage needs to meet the stability of ±0.1%. For example, if the reference voltage is 10V, a fluctuation of ±0.01V can be allowed. If it is not, it will cause a display fluctuation. But if the amplitude of the display fluctuation at this time does not exceed the amplitude of the fluctuation voltage, then the potentiometer sensor is normal.5) As for the linear displacement sensor installation, the parallelism can be allowed to have an error of ±0.5mm, and the angle can be allowed to have an error of ±12°. However, if both are too large, then the display number will be bounced. So the parallelism and angle must be adjusted.6) During the connection process, be sure to pay more attention, the wires of the potentiometer sensor cannot be connected wrongly.   Ⅷ FAQ 1. What is a linear displacement sensor?A linear displacement sensor is a device used to monitor and measure linear position. They can also be called Linear Position Sensors or Linear Transducers. They are available in different sizes to measure different stroke lengths.   2. How does a linear displacement sensor work?Linear displacement transducers are linear sensors that work on the magnetostrictive principle, whereby a torsional strain pulse is induced in a specially designed magnetostrictive waveguide by the momentary interaction of two magnetic fields.   3. What is the linear displacement?Therefore; “Linear Displacement” can be defined as the movement of an object in a linear fashion along a single axis in a straight line, for example; from side to side or up and down. ... Linear Displacement is usually measured in millimetres or inches and has a positive and negative direction.   4. What are linear sensor potentiometers?A linear potentiometer is a type of position sensor. They are used to measure displacement along a single axis, either up and down or left and right. Linear potentiometers are often rod actuated and connected to an internal slider or wiper carrier.   5. What is the difference between linear potentiometer and rotary potentiometer?This potentiometer is similar in function to the rotary potentiometer. The only difference between these two, as the name suggests, is the linear motion of the knob, instead of rotary, for adjusting the resistance.   6. How does a potentiometer sensor work?Potentiometers work by varying the position of a sliding contact across a uniform resistance. ... A potentiometer has the two terminals of the input source fixed to the end of the resistor. To adjust the output voltage the sliding contact gets moved along the resistor on the output side.   7. What does a potentiometer sensor measure?A potentiometer sensor measures the distance or displacement of an object in a linear or rotary motion and converts it into an electrical signal.   8. How does a potentiometer measure displacement?To measure the displacement of the body, this body, which is moving, is connected to the sliding element of the potentiometer. As the body moves, the position of the slider located on the potentiometer also changes so the resistance between the fixed point and the slider changes.