Chapter 845 Optoelectronics Coupling
The benefits of controlled primary and secondary isolation are self-evident. Problems on one side will not affect the other side. Especially when the secondary has high voltage, high current, high power, and a complex working environment, reliability and maintenance performance can be greatly improved. .
To give a simple example, if the secondary is struck by lightning, the impact of the lightning strike can theoretically only reach the isolation switch, and the controllers above are protected. These days, the controllers above are expensive.
The question is, how to isolate?
"Gao Chief, is this used in the DC circuit? How to isolate? Is it a barrier transformer? That thing can only be used in the AC circuit." President Cui has nothing to do with Gao Zhendong, but he is really he really, he really, he really, he is really. not understand.
He did not mention the electromagnetic relay that also had the same isolation function. He was engaged in this electronic switch to solve the defect of relay. It was useless and went back.
In fact, what he said is not entirely correct. It is not that there are no isolation transformers used in DC circuits, but it is more troublesome. Gao Zhendong did not dwell on the issue of isolation transformers. He used other methods to solve it. The isolation transformer is not small, and there are Special function, but nothing else fits here.
"Not isolation, we use an optoelectronics coupler!"
Optocoupler? Now Mr. Cui and Pan Chang were really confused. What the hell is this? Never heard of it! Chief Engineer Gao's place is full of new things, but it's a bit unfriendly to those who communicate with him.
They have not heard that they are right. The principle of photoelectric coupling is proposed in 1963, and now the world does not know.
If you don’t understand, just ask: “Mr. Gao, what is an optocoupler?”
"Ah, this is a newly designed isolation switch device that uses photoelectric principles to couple the primary and secondary, so I named it a photoelectric coupler."
It turned out to be a new design of Gao Gao workers? That's okay.
In this case, the comrades of 1218 are a little excited, and are they new? Hi, how are you embarrassed?
They know that this means one thing: another first prize of the Lightning Technology Award has been obtained!
It's a new component, and it's a brand-new one in principle. It won't win the first prize, and the ministry won't agree to it.
If the situation of electronic electronic components is not clear now, at least this electronic switch is enough for them to be happy.
"Mr. Gao, you tell me and we will remember it." New things can only be learned from the beginning. There is not much room for discussion. It is not too late to discuss after learning.
Gao Zhendong stood up and picked up the chalk.
"Actually, the principle is very simple. Everyone knows the photoelectric effect, right?"
Without waiting for anyone to answer, he continued talking on his own, not knowing what to do.
"This device actually has a simple structure. The primary controls a light-emitting element, which supplies power to emit light when it is turned on. The secondary is a photosensitive element, which turns on when it senses light. Of course, this is a normally-on element. Normally closed components are on the other hand, they are on when the primary is not emitting light, and are off when the primary is emitting light.”
The normally open and normally closed contacts mentioned in the electronics industry are terms that can easily confuse ordinary people. The "open" here refers to open circuit or disconnection, and the normally open type refers to the normal state of "disconnection". It's not the normal "open", it means exactly the opposite.
Correspondingly, the normal closed type refers to the normal "closed", which is the opening of the switch, not the normal "shutdown". For ordinary people, full twisted.
This is exactly the opposite of the constant opening, normally closed fire doors, and the frequent and normal closed security doors in security.
Fortunately, the people here understand this. They are all marveling at Gao Zhendong's fantastic idea. Hey, using a photoelectric switch, doesn't the primary and secondary levels be isolated?
high! It’s really high!
Chief Engineer Gao's surname is Gao, which makes sense.
"Hey, this idea is good, safe!"
"Not only safe, so that if the sensitivity element is properly selected and the current controls the current, it will not merge to the output pole. For some sampling circuits, this will further improve the sampling performance." This is the chief worker Cui. Experienced senior technical personnel think more and more than ordinary people.
"This is a bit of relay, haha." Well, I still went back
"What is better to use this luminous device? Hurbing lamps can be integrated. It is not unavailable to use here, but it feels that the effect is not very good." A comrade asked.
What he thought was very reasonable, incandescent lamps and even light tubes had a volume problem.
Gao Zhendong hasn't answered yet, President Cui has laughed: "You are stupid, used in the best light device here, our factory is not producing, hahaha."
Everyone suddenly realized, hey, how did you forget this!
Our factory's LED is the only one. Maybe the chief worker chose us 1218, there is a reason for this.
Gao Zhendong nodded: "Yes, use LED, and don't have visible light LED, the efficiency of white light is too poor."
The white light spectrum is fully and uniform, which means that under the same power, its power is basically allocated on the bands, but the light sensitivity element is selective. Generally Okay, so, those energy that is not within its wavelength range is blind.
"What do you use?"
"Use infrared rays, gallium arsenide, and can directly emit infrared rays directly." Gao Zhendong answered without thinking. This is unheard of for the comrades of 1218, but here is just as simple as the Gao worker.
Although they don't know what "direct energy gap material" is, but Chief Engineer Gao said it can emit infrared rays, so it must be possible.
But there is a problem.
"Where do gallium arsenide comes?" You do n’t have to ask anything. They still know the lead -oriented lead.
But they don’t even know where to get this thing!
Gao Zhendong froze and cared about it.
"Haha, don't worry about this, I'll solve it."
Gallium arsenide can be pulled out using the Cz method, which is a bit more troublesome, but it can be pulled out. However, the quality of the crystals pulled out is not very high, but it is still no problem when used in light-emitting components, and the amount used is extremely small, so it should be fine. Supportable.
The CZ straight method is that Gao Zhendong and the single crystal furnace is this method.
As a senior military fan of the technical stream, Gao Zhendong collected a lot of gallium arsenide-related materials in his previous life, but he just needed one person to be responsible for the implementation.
There is no mistake, one, one, one, one, one, one, one, one 619, one book, one, one, one, one, one, one, a book!
Tang Shaohui: Huh? How do you feel sneezing?
In Gao Zhendong's previous life, gallium arsenide became practical only two years later. In fact, it is not as rare as most people think.
Hearing Gao Zhendong's words, the comrades in 1218 suddenly remembered where they were sitting.
Seventeen Organization Three -Rolling Factory and Three Plant! Materials are the main business of others! Think about how high pure single crystal silicon comes?
That's okay.
"Then we will use ordinary LEDs to make samples first, and then replace them when the gallium arsenide material comes out." He is experienced in arranging the schedule of the project. It can be done without gallium arsenide, but the efficiency is not as good, but there is Those are two different things. There are technical means to make up for the poor efficiency. There is no best, and the second best does not mean it cannot be used.
The wavelength range of LEDs of various colors is actually limited to a certain range, which is much superior to white light.
Although many LEDs look red, yellow or green, it seems that the light is dyed by the plastic package to show those colors. In fact, it is not the case. The colors of these plastic packages are just for the convenience of users to distinguish, even if it is made of completely transparent plastic Encapsulation, people’s light is still red as it should be, yellow as it should be, it’s the color it’s born with.
"Well, your arrangement is fine, first use the visible monochrome light, which is at least stronger than the white light." The arsenidized hair light pipe is basically standard for all later light coupling, but before that, it was used for a while. Visible light is not unavailable. It is always stronger than incandescent lamps and light tube.
"Mr. Gao, on the photosensitive side, I have thought of a lot of possibilities, but they feel a bit confusing. Please help me sort them out." Mr. Cui said with a smile. He has thought of several ways, but he hasn't fully figured it out yet. .
"Well, you tell me and I listen. If you don't understand something, I'll explain it to you."
Although he didn't know what Cui thought of, Gao Zhendong confident that in the current environment, he could think of it.
Comrades can think of their own solutions and take the initiative, which is something Gao Zhendong can only hope for.
Mr. Cui thinks so too.
"The first photosensitive method I considered was to use a photoresistor, but I always felt that something was wrong."
As long as you are engaged in optoelectronics, this is definitely the first thing that comes to mind. Photoresistor has the advantages of high linearity, simple structure and low cost.
But the photoresistor has a fatal flaw.
"Well, photoresistor can realize this principle, but photoresistor has a fatal problem. The switching speed is too slow. Not to mention high-speed circuits, low-speed circuits are too slow."
The switching speed of the light -sensitive resistance is extremely slow, and the worst can reach hundreds of milliseconds. It is probably the treatment of sitting at a table with electromagnetic relays.
Gao Zhendong reminded that Cui always remembered that this thing was really the disease.
"Then it won't work. What we want to do is a high-speed electronic switch." Mr. Cui knew the purpose of this project very well.
Gao Zhendong did not completely deny: "Not necessarily, you can do it by the way. After all, this thing can really be isolated, and the volume is far better than the electromagnetic relay. At the same time, the structure is extremely simple and the cost is low. It has a certain role and high lineivity, and in special cases, it is also used. "
The optocoupler of this kind of photoresistor is really simple to the extreme. In theory, it is enough to package a light-emitting tube and a photoresistor face to face. The reason why the shell is needed is mainly to prevent external light from interfering. to the photoresistor.
(End of this chapter)