Soul Returns to Hong Kong: From Tailor Shop to Richest Woman

The next morning was for an electronics circuit experiment class; the laboratory building was at the northernmost part of the campus, and there were many old instruments in the corridors, with safety operating rules posted on the walls; the first rule was that it was strictly forbidden to disassemble equipment while it was powered on, and two horizontal lines were drawn in red after it.

The teacher in charge of the lab class was Mr. Zhou, who was in his thirties and had his sleeves rolled up to his elbows. "Today we're going to do the most basic amplifier circuit."

Teacher Zhou placed a box of electronic components on the podium: "Work in pairs and collect resistors, capacitors, transistors, and circuit boards. Solder them first, then measure the static operating point."

Sun Miaoshu immediately moved next to Lin Ying. "Let's be a team. You'll be in charge of the technical aspects, and I'll be in charge of following instructions."

Lin Ying looked at her: "Are you planning not to learn anything at all?"

"I'll learn, I'll take responsibility for learning diligently from the side."

Liu Yang turned around and laughed, "Sun Miaoshu, you've got a good plan; you're in a group with Cambridge graduates, so you don't even have to worry about the lab report."

Sun Miaoshu glared at him: "You wanted to come, but there aren't even any seats available!"

Teacher Zhou tapped the table: "Stop chatting, get your things first; there are eight oscilloscopes in the lab, handle them with care, if one breaks, we won't have any new ones for the rest of the semester."

Lin Ying retrieved the components and arranged them according to their values. The theoretical part was fine, and the circuit diagram was simple; the problem lay in the soldering. She picked up the soldering iron, but her movements stopped...

Sun Miaoshu asked, "What's wrong?"

"I haven't touched this in a long time."

"Aren't you studying electronics?"

"I originally studied mathematics, and I added the electronics myself later."

Sun Miaoshu's relaxed expression immediately vanished by half: "Then can you solder?"

Lin Ying looked at the circuit board on the table: "Probably."

"should?"

"I understand the basic principles."

Sun Miaoshu became even more nervous: "I suddenly feel that our group's technical capabilities aren't that stable."

Lin Ying inserted the resistor leads into the board holes according to the solder joint locations and heated them with a soldering iron; as soon as the solder was applied, the molten solder spread out and connected the two adjacent solder joints as well.

Sun Miaoshu stared at the lump of tin: "Is this normal?"

"This is not normal."

"Is there any way to save him?"

"Okay." Lin Ying used a desoldering pump to remove the solder, but the first time she didn't remove it completely; the second time she tried, the soldering iron touched the outer sheath of the wire next to it, and a burnt smell immediately filled the air.

Sun Miaoshu took a step back: "Lin Ying, I think it needs to be lit."

"It won't light up; the power isn't connected yet."

Teacher Zhou walked over from behind, glanced at their blackboards, and said, "Lin Ying."

"Teacher Zhou."

"Are you planning to let the current choose its own direction with this solder joint?"

The boys next to him all laughed.

Liu Yang peeked over and chuckled, "So there are things you don't know too!"

Lin Ying put down the soldering iron: "When did I ever say I could do everything?"

"We've already accepted that you've never answered a question wrong in class."

Teacher Zhou picked up the circuit board to inspect it: "The three solder joints are connected together, and there is also a cold solder joint; no matter how good the theory is, it's useless if the circuit can't be connected."

"I'll redo it."

"Don't rush to redo it." Teacher Zhou put the board back. "Practice soldering first. There are scrap boards under the experimental cabinet. Take out two of them. Only when you can solder them perfectly round can you start working on the actual circuit."

Sun Miaoshu asked softly, "Teacher, what about the lab report?"

"You still have the nerve to ask about the lab report?"

"I care about my learning progress."

"First, learn to identify all the color bands on the resistors." The two were assigned to a corner of the laboratory.

Sun Miaoshu examined each resistor in a bundle one by one, while Lin Ying practiced soldering with scrap boards; the first row of solder joints were of varying sizes, the second row was finally more neat, and the third row met Teacher Zhou's requirements.

By the time they resumed the formal experiment, the other groups had already connected to power and were measuring data.

Sun Miaoshu kept glancing at the clock: "There are still forty minutes left, is that enough time?"

"There's enough time. Just insert the components according to the diagram, and I'll solder them."

"Won't it all merge together this time?"

Lin Ying looked up: "If you ask again, I'll make you solder."

Sun Miaoshu immediately handed over the resistor: "I believe you."

The second time went much more smoothly.

Ten minutes later, all the components were soldered; Lin Ying checked the circuit to make sure there were no short circuits before connecting the DC power supply.

The ammeter did not register any response.

Sun Miaoshu's face fell immediately: "It's over, it's still bad."

Lin Ying turned off the power and re-inspected the solder joints.

The soldering was fine, and the component positions were correct; she used a multimeter to measure segment by segment, but when she measured the input end, the data was incorrect.

"Teacher Zhou, this resistor is labeled as 10,000 ohms, but its actual resistance is less than 1,000 ohms."

Teacher Zhou came over and tested it once, then took out a resistor of the same specification from the box for comparison: "This color ring is printed wrong."

Sun Miaoshu immediately perked up: "We didn't break it while welding?"

"no."

"I knew it! Lin Ying would definitely do well the second time!"

Lin Ying reminded her, "You finished speaking just five minutes ago."

"That was a necessary risk warning."

After replacing the resistor, the circuit returned to normal.

Lin Ying adjusted the input signal and observed the output waveform with an oscilloscope, quickly measuring the voltage amplification factor. She then changed two parameters and recorded the distortion point and cutoff region data together.

After watching from the side, Teacher Zhou remarked, "You're not skilled at welding, but you're quick at taking measurements."

"I'm pretty good at math."

"Experiments are not math problems; equipment has errors, and components have errors; don't just look at the nominal values ​​in the future."

"I've got it."

When the bell rang, Sun Miaoshu, carrying her lab records, walked with a lighter step: "Lin Ying, we weren't the slowest in the end after all."

"The power cord in the next group is connected backwards, and we are still checking it."

Liu Yang caught up from behind: "Don't even mention it. It's our group. Chen Jian is really good at drawing circuit diagrams, but he can still get the colors wrong when wiring."

Chen Jian chimed in, "Red and brown are inherently difficult to distinguish after a while!"

"You connected the black wire wrong too. You know what black is, right?"

The three of them argued all the way to the cafeteria entrance.

Just as Lin Ying was about to go inside, Professor He called out to her from behind: "Lin Ying, don't eat yet, come to my office with me."

Sun Miaoshu clutched her lunchbox tightly: "Is it the logistics department again?"

"Not this time." Professor He glanced at her. "Also, we've already explained the humidifier issue to the dorm manager. As long as the power consumption isn't exceeded, it's allowed to be used."

Sun Miaoshu immediately smiled: "Professor He, you are such a good teacher!"

Professor He waved his hand: "Stop flattering me, go eat."

Upon arriving at his office, Professor He took out a key and a temporary access pass from his drawer.

"The school has arranged a small laboratory for you on the fourth floor of the information building. It's not very big, and the equipment isn't complete. We'll use it for basic verification first."

Lin Ying took the access pass: "Can I use it now?"

"It can't be used alone yet. Engineer Tang from the lab will guide you, but he must be present when dealing with high-voltage power supplies and expensive instruments."

When is Engineer Tang available?

"He's already waiting for you."

The two went to the information building.

The door to the innermost room on the fourth floor was open, and a man in his fifties was sitting at a workbench repairing circuit boards. The table was covered with tools, and there wasn't even enough room to stand.

Professor He knocked on the door: "Old Tang, the person has been brought to you."

Engineer Tang didn't look up: "The one from Cambridge?"

"right."

"Wait a bit."

Professor He winked at Lin Ying, then turned and left...

Lin Ying stood at the door for more than ten minutes. Engineer Tang finished repairing the circuit board in his hand, plugged in the test wires, and confirmed that the indicator lights were normal before looking up at her.

"I heard you're very good at theory."

"Well enough."

"Can you solder circuit boards?"

Lin Ying paused for a moment: "I just ruined one of them by welding today."

Engineer Tang finally looked at her properly: "You dare to admit you messed up the weld, not bad."

He took a bag of scrap components from the cabinet and placed it on the workbench: "Forty solder joints. Remove them, then solder them back. Don't damage the pads or burn out the components. I'll check them when they're done."

Lin Ying asked, "Is this an entry-level assessment?"

"This isn't a test; it's to prevent you from ruining expensive circuit boards in the future."

"When is it due?"

"Tomorrow afternoon."

Lin Ying glanced at the bag of components: "What time does the lab close tonight?"

"Ten o'clock."

"I'll come back after I finish eating."

Engineer Tang lowered his head and continued repairing the equipment: "Let me make this clear first, I don't care if you're a genius or not. Once you're here, you'll have to pick up the screws yourself if they fall on the ground."

Lin Ying carefully put away her access pass: "Don't worry, I'm not so rich that I'd hire someone to pick up screws for me."

Engineer Tang paused for a moment: "Go eat quickly. Be back in half an hour. Every minute late means you'll have to weld ten more."

Lin Ying turned and left, saying, "Teacher Tang, this isn't education, it's loan sharking."

"Twenty-nine minutes left."

Lin Ying.........