Rebirth of America, this is my time

When Ethan stepped into Evelin's experimental base again, what he saw was an empty table and a clean space. The neatly gathered tools and components piled in the corner seemed to be It tells the story of the owner's hard work, but the broom and dustpan lying casually tell the story of the user's carelessness.

Ethan bent down and put these things in place, but Evelin shook her head repeatedly when she saw the obsessive-compulsive behavior.

"I left it there on purpose because it would be easier to pick it up."

"But it's not pretty." Ethan replied with a smile.

"Oh, okay, as long as you're happy."

This waste of time made Evelin sneer. She was in a good mood and was too lazy to argue with her brother.

He patted the table and brought everything back to the topic.

"Ethan, making something like a circuit board is actually very simple. The first step is to draw a circuit diagram."

"Since you have not studied this aspect systematically, I will save this part of the explanation first. If you want to learn, I can teach you later. Now, I will use the circuit diagram I designed last night to make the board. "

She shook the paper in her hand.

There are dense lines drawn on it.

"After you have the circuit diagram, the second step is to cut the copper plate so that its size matches the size of the circuit board you want."

Perhaps she had come to the field that she was best at. At this moment, Evelin stood in front of the operating table with a confident expression on her face.

She picked up a piece of copper-clad board that Ethan had just bought with her fingers and said: "You'd better remember all the things I'm going to say below, because in the future, whenever it comes to the production of circuit boards for small-scale objects like this, we will use them. It’s this kind of board today. The board you see now is called phenolic paper-based copper-clad board. It uses phenolic resin as the adhesive, wood pulp fiber paper as the reinforcing material, and the surface is also covered with a layer of copper foil.”

As she spoke, she tapped the copper plate with her fingers.

That crisp voice sounded like it was saying——

‘I’m a good player. ’

"You'd better remember the specific dimensions. The total thickness of this board is 63 mils, and the thickness of the copper foil layer is 1.4 mils. This data is a near-perfect small circuit board data measured by countless engineers through personal experience."

"Because the greater the total thickness of the copper-clad board, the harder it is and the harder it is to process. The smaller the thickness, the softer it is and the easier it is to deform. What's more fatal is that at the same time, the heat resistance of the board will also change. Very bad."

"The thickness of the copper foil layer will affect the conductivity, heat resistance and anti-interference performance of the circuit board. The thicker, the better the conductivity, and the thinner, the worse the conductivity, and it is also easy to crack and break."

To be honest, Ethan knew that rubbing the circuit board by hand might be troublesome, but he didn't expect it to be so troublesome.

A small circuit board. Just the board itself has to be carefully selected in terms of materials?

This was an area he had never imagined.

However, the clearer Evelin described it, the safer he felt.

Because only those who have something in their stomach dare to explain everything in detail, and the half-filled bucket of water is the most afraid of showing cowardice.

This is also true. After Evelin introduced the various materials for making the circuit board, she started to operate it steadily.

First, take out a piece of wax paper, lay it flat on the steel plate of the workbench, use a pen to carve the pre-designed circuit diagram 1:1 on the wax paper, and then compare it to the wax paper, and start from a 41-inch × 49-inch piece. Cut out a small board from the copper clad board and trim it to the size of the circuit diagram.

After finishing, neatly paste the wax paper with the circuit diagram on the cut copper-clad board with double-sided tape.

Then, Evelin asked Ethan to put on the mask for chemical work, opened the paint, took out the talcum powder, mixed the two into a printing fluid with moderate viscosity, then dipped it in with a brush and applied it evenly in the same direction. On wax paper.

Since there is no technical difficulty in this link, Ethan can operate it very quickly.

But at the same time, he also had a problem.

"Why does this thing have to be brushed in one direction?"

"Wouldn't it be more convenient to brush repeatedly?"

"It's very simple. Repeated brushing will easily wrinkle the wax paper and break it."

Although Ethan asked an idiotic question, Evelin did not mean to laugh at this moment, but explained seriously: "If it is a plastic model in the factory, you can paint it wildly, but you must be careful when making it by hand. Because once the lines on the copper plate overlap, the effect of the board will deteriorate or even be scrapped."

"learn."

Ethan felt like he had learned something.

After the circuit was printed, Evelin asked Ethan to place it in a ventilated place to dry.

This process requires waiting, so the two of them took this time to go to the kitchen and get some food.

Ethan made an omelette sandwich, but unfortunately he didn't control the heat well and one side was burnt.

But that's not important, right?

At this moment, their minds were focused on the production of circuit boards. After eating casually, they returned to the garage.

As the board dries, the next step becomes very important, because they need to remove the non-circuit parts and use corrosive liquid to corrode the unused copper surface. This step is performed by Evelin.

I saw her carefully taking out the potassium chlorate that Ethan bought, using an ounce scale to weigh out 1 dram, and then mixing out 8 teaspoons of 15% hydrochloric acid, and mixed them together.

Next, apply the circuit board very carefully.

Although the chemical protective mask was not comfortable to wear, Ethan was very relieved to see Evelin's steady movements.

During the process, she also said: "Ethan, actually there is a wild way to operate this step. Some people like to prepare a ferric chloride solution, which is 40% ferric chloride plus 100% ferric chloride. 60/60% water, and then rinse the circuit board directly. If you do that, the corrosion will be completed quickly, but I don’t like it because I don’t control it well and often splash the solution everywhere.”

The honest words made Ethan laugh.

"It doesn't matter. The most important thing is to be impatient when doing things, right? We are not competing and we are not in a hurry."

Ethan only replied and then shut his mouth, he didn't want to distract Evelin.

Evelin didn't speak again and concentrated on her work.

After she corroded away the excess copper layer, she asked Ethan to bring the water that had been prepared to rinse the plate.

After making sure there was no residue, she asked Ethan to open the banana water and wipe off the paint on the circuit after bending down for a long time.

Following Ethan's movements, a board with a green background and a copper core also appeared.

At this point, things are not over yet.

Next, Evelyn punched holes in the board while Ethan, under her guidance, mixed rosin and acetone.

"The thing you are mixing now is called flux. Applying it to the circuit board can remove oxides and oil stains, prevent re-oxidation, and increase the welding area. It is very helpful for welding."

While speaking, Evelin had already applied flux to the board.

Then, the whole garage was filled with green smoke.

Because the solder wire contained a certain amount of lead, Evelin was still wearing protective gear. In this case, Ethan couldn't see her face clearly at all, but sitting beside him, he could feel the serious.

I don’t know how long it took, but when a sound of relief appeared, Ethan finally came back to his senses.

"Is it done?" Ethan asked in surprise.

The next second, he also looked at the clock on the wall.

The pointing at midnight made him quickly say: "Thank you for your hard work."

"Oh Ethan, this is the first time I hear this from your mouth. You used to say thank you sister."

Evelin took off the protective gear and said with a smile: "But I like the feeling now."

"When you used to say thank you, it was just perfunctory."

After teasing Ethan, Evelin held up the circuit board again and said, "I haven't done much of this kind of thing, and I don't know if there is a problem with the soldering, so why don't you give it a try?"

This suggestion made Ethan very happy, and he took the initiative to hold out the TV set used for yesterday's demonstration.

The monkey's anxious look made Evelin laugh without saying a word.

She connected the circuit board to the TV and powered it on.

After a flash, countless snowflakes appeared on the TV screen.

This sight made Evelin frown slightly, and then she knocked on the table hard.

There was just a crisp sound of "clang", the steel plate on the table whined, and the TV set on the table suddenly shook. The next second, the snowflakes on the screen disappeared instantly, replaced by a black world.

This world is framed by white lines.

In the middle of the box, there is a pixel strip half as long as a finger.

After it appeared, it first stayed in place for three seconds, and then moved forward bravely to the right.

It took about five seconds to complete the NTSC standard TV horizontal path and walked through about 300 pixels.

Then, he hit the white border.

Then, the screen vibrates.

Huge words appeared in the center of the screen——

Game Over.

Note: ① According to the memories of Apple founder Steve Wozniak, in the 1970s, the process for people to make video games was almost like this, and the time was about 4 days to a week. What people at that time lacked was not Technology, but inspiration. ②NTSC: National Standards Committee of the United States.