Sign Up
Your Martial Arts Social Media helps you connect and share with the people in your life.
Search Blogs...

Topic: circuit

perrilshy

by
Circuit breakers are automatically-operated electrical safety devices that protect homes from power surges and overloads. They also guard against fire and blackouts. They need to be replaced at least every 30 years. The most often tripped breakers can be a indication that your electrical panel is overwhelmed. Moving appliances onto a different circuit could help ease the issue. Refurbished circuit breakers for sale In general, electrical breakers last 30-45 years. But, they may be replaced sooner if you reside in a region that is prone to frequent power outages or brownouts. The electrical safety devices are made to stop the electricity flow when they sense an overload. If the circuit breaker in your home's panel is deteriorating It could be the time to change it. A malfunctioning electrical circuit breaker could cause serious damage to your house, which is why it is essential to take the necessary steps to avoid it happening. The best way to prevent this is to purchase used breaker from a reputable supplier. They are usually refurbished and tested to make sure they are in line with industry standards. They're also cheaper than brand new models, which makes an excellent choice for people on a tight budget. Modern homes are constructed using 100 amp electrical wiring. But older homes may be wired with 60 amps. If you're not certain the wiring in your house is current It is recommended to consult a professional electrician in your area. They will be able to help you determine the kind of breaker you have and the power of your house's electrical power. There are a variety of signs to indicate that the breaker you have is older and requires to be repaired or replaced. If, for instance, your breaker is constantly triggering, this is most likely due to an overloaded circuit. It could be because of the amount of appliances you are using in your house, or perhaps it's due to the fact that your breaker isn't adequately protecting the electrical circuit. Breakers with mold The molded breakers are one type of circuit breaker that's designed to safeguard electric systems from overload as well as fire hazards. They are made to handle large currents, and are typically employed in industrial settings. They also serve to regulate the flow of power through the circuit board. They come in various dimensions and are able to be mounted either in a vertical or horizontal orientation. The breakers come with a plastic case which houses the contacts as well as the chambers for arc extinguishing and an the operating mechanism. The case is constructed of glass polyester that provides an unconducting structure and impedes the development of fungi. The breakers are also approved to be used in a broad variety of temperatures. It is crucial to remember that the characteristics of tripping on these used circuit breakers for sale can change in response to changes in temperature. Certain molded case breakers come with electronic trip devices that can be customized for particular applications. They can be more tolerant to short circuits. This is why they are ideal in medical or computer devices. They also have the ability to identify higher values of fault current over other kinds of MCCBs. MCCBs can also work with capacitor banks. They aid in reducing line currents as well as reduce utility costs. MCCBs can also be utilized to power large electric generators that typically draw high flows of current. In the end, these gadgets can aid in reducing the chance of damage to costly equipment. Vacuum circuit breakers Vacuum circuit breakers are becoming more often in switchgear with medium voltage applications. They are able to withstand high levels of interruption and need minimal maintenance when compared with other kinds of circuit breakers. They also are quieter and smaller than bulk or air circuit breakers. They are suitable for many different environments, for example, commercial and industrial settings. The vacuum circuit breaker cuts off current by breaking the connection between fixed and moving contacts. If these contacts break and a arc strikes between them. This creates an ionic vapor of metal that is dependent on the materials of the contact. The arc quickly disintegrates through the motion of metal electrons and ions. This is the reason why vacuum breakers are so strong in dielectric power. They can cut off the flow of electricity without releasing dangerous gases, which makes them an alternative that is safer than SF6 gas. They are also able to be closed frequently, in contrast to other circuit breakers that have to be waited for contacts to cool between closings. They're also cheaper as compared to other kinds of circuit breakers and do not require a separate auxiliary oil management system or an oil handling. They are perfect for commercial and industrial use They come with an array of designs. They come in a range of sizes ranging from 6.6 up to 33 kV. They are suitable for a variety of locations, from hotels to water treatment facilities. These can also be utilized for high-voltage projects like substations and power plants. Air circuit breakers Circuit breakers for air are a kind of electric device used to safeguard low-voltage equipment like capacitors, as well as industrial machines. They also provide protection against ground faults as well as other hazardous conditions. They're a great option for power stations and other establishments that need reliable energy. They are simple to set up and use as well as provide security and dependability. In contrast to oil circuit breakers that require replacement frequently, air circuit breakers are much simpler to maintain and use. They're less prone to mechanical strain, which means they do not require lubrication or continuous surveillance. This is an excellent benefit for companies looking to cut costs and improve effectiveness. The market worldwide of air circuit breakers is growing quickly due to the growth in renewable sources of energy as well as the increasing need for continuous energy supply. Additionally, nations in Asia-Pacific expand their manufacturing as well as infrastructure development projects that need advanced electrical systems capable of handling the demands. Circuit breakers for sale on surplusrecord....
Topics: used, circuit, breakers
crystalyang

by
TL431 is a precision voltage regulator, and PC817 is a photocoupler. In switching power supplies, the design of the voltage regulator feedback circuit is usually carried out with the cooperation of TL431 and PC817. In the flyback power supply design, the feedback circuit often uses them as a reference. Therefore, the cooperation between the two is always a topic that engineers like to talk about. This article comes from the technical expert of the forum, and uses the typical application of TOPSwicth to illustrate the cooperation between TL431 and PC817. First of all, let’s take a look at TOPSwicth-based, TL431 and PC8 TL431 and PC817 use the circuit diagram Next, with reference to Figure 1, the parameters in the circuit diagram will be analyzed and explained. If you want to understand the relationship between the two, you must first determine the values ​​of the four parameters R1, R3, R5, and R6 in the TL431 part of Figure 1. Let the output voltage be Vo, and the rectified output voltage of the auxiliary winding be 12V. The circuit compares the output voltage with the reference voltage formed by TL431, and controls the C pole of the TOP tube through the current change of the photocoupler PC817, so as to change the PWM width and achieve the purpose of stabilizing the output voltage. Because the controlled object is the TOP tube, it is first necessary to understand the control characteristics of the TOP tube. From the technical manual of TOPSwicth, it can be seen that the current Ic flowing into the control pin C is inversely proportional to the duty cycle D, as shown in Figure 2 Figure2-Relationship between TOPSwicth duty cycle and control current The current of Ic should be between 2-6mA, and PWM will change linearly, so the current Ice of the PC817 triode should also change in this range. And Ice is controlled by the diode current If, through the relationship curve between Vce and If of PC817 (as shown in Figure 3), the forward current If of the PC817 diode can be correctly determined. It can be seen from Figure 3 that when the forward current If of the PC817 diode is about 3mA, the collector-emitter current Ice of the triode changes at about 4mA, and the collector-emitter voltage Vce changes linearly in a wide range, which meets the control requirements of the TOP tube . Figure 3 The relationship between PC817 collector-emitter voltage Vce and forward current IF Therefore, it can be determined that the forward current If of the PC817 diode is 3mA. Looking at the requirements of TL431, it can be known from the technical parameters of TL431 that when Vka changes from 2.5V to 37V, Ika can vary in a wide range from 1mA to 100mA. Generally, 20mA is enough, which can not only work stably but also provide some dead load. However, for TOP devices, because the dead load is very small, only about 3-5mA can be selected. The above relationships are very important. With their foreshadowing, the resistance values we mentioned at the beginning of the article are easier to determine. According to the performance of TL431, R5, R6, Vo, and Vr have a fixed relationship: Vo=(1+ R5/R6) Vr In the formula, Vo is the output voltage, Vr is the reference voltage, and Vr=2.50V, first take a value of R6, for example, R6=10k, and R5 can be calculated according to the value of Vo. Then determine R1 and R3. As mentioned above, the If of PC817 is 3mA, and the value of R1 is 470Ω, then its voltage drop is Vr1=If* R1. According to the PC817 technical manual, the typical value of the forward voltage drop Vf of the diode is 1.2V, then The voltage drop Vr3=Vr1+Vf on R3 can be determined, and the current Ir3=Ika-If flowing through R3 can be determined, so the value of R3 can be calculated: R3=Vr3/Ir3= (Vr1+Vf)/(Ika-If ) According to the above calculation, the cathode voltage value Vka of TL431 can be known, as Vka=Vo’-Vr3, where Vo’ is 0.1-0.2V larger than Vo, for example, Vo=15V, take R6=10k. R5=(Vo/Vr-1)R6=(12/2.5-1)10=50K; Take R1=470Ω, If=3mA, Vr1=If R1=0.003*470=1.41V, Vr3=Vr1+Vf=1.41 +1.2=2.61V. Take Ika=20mA, Ir3=Ika-If=20-3=17, R3= Vr3/ Ir3=2.61/17=153Ω. The cathode voltage value Vka of TL431, Vka=Vo'-Vr3=15.2-2.61=12.59V. Results: R1=470Ω, R3=150Ω, R5=10KΩ, R6=50K. In this way, the resistance values of several key resistors are successfully obtained. However, some friends may not fully understand it, and more detailed supplements from technical experts will be attached below. Regarding the value of R6, the resistance value of this parameter is not determined arbitrarily. There are two factors to consider, first, the current at the TL431 reference input. Generally, this current is about 2uA. In order to avoid the current at this terminal from affecting the voltage division ratio and avoiding the influence of noise, generally the current flowing through the resistor R6 is more than 100 times the reference segment current, so this resistance should be less than 2.5V/200uA=12.5 K. Second, the requirement of standby power consumption. If there is such a requirement, try to take a large value under the condition that it is less than 12.5K. TL431 requires a working current of 1mA, that is, when the current of R1 is close to zero, it is also necessary to ensure that TL431 has 1mA, so R3≤1.2V/1mA=1.2K. In addition, there are also power consumption considerations. The value of R1 should ensure that the TOP control terminal can obtain the required current. Assuming PC817A, it's CTR=0.8-1.6, the lower limit is 0.8, and the maximum current flowing through the photodiode is required to be 6/0.8=7.5mA, so the R1 Value≤(15-2.5-1.2)/7.5=1.5K, the maximum current that the photodiode can withstand is about 50mA, TL431 is 100mA, so we take the maximum current flowing through R1 as 50mA, R1>(15-2.5-1.3 )/50=226 ohms. In order to increase the gain at low frequencies and suppress low-frequency ripples, R5C4 is required to create a pole at the origin. That is the static error. R4C4 forms a zero point to increase the phase. It should be placed in front of the bandwidth frequency to increase the phase margin. The specific position depends on the phase of the rest of the power part at the design bandwidth. The lower the frequency of R4C4, the lower the frequency. The higher the boosted phase, of course, the maximum is only 90 degrees, but the low-frequency gain will also be reduced when the frequency is very low, generally placed at 1/5 of the bandwidth, and the boosted phase is about 78 degrees....
Topics: circuit