Li Jinqiu's remaining words were glared back with angry eyes from Deputy Mine Manager Zhang.

Guo Qian looked at the two black circuit boards thrown aside, and then looked at the paper "circuit boards" made by Jiang Xinwei, and asked in a low voice: "Master Jiang, the two circuit boards you took out from the switch have so many pins connected to the switch, and there are only a few pins on your paper circuit board?"

The meaning of her question is not only to suspect that these two circuit boards are missing, but also to believe that this is too simple because of ugliness, isn't it? I have seen a lot of waste utilization, but I have never heard of using cardboard to make PCB circuit boards, and I absolutely do not believe that they can be used.

Jiang Xinwei naturally understood the meaning of her question, and said, "Don't worry, I promise to get the phone through." ”

Although she listened to his assurance, Guo Qian still didn't believe it.

No one in the computer room will believe it, what he made really does not match the tall switch in their impression, the switch is high-tech, how can such a garbage thing be used?

They don't know that Jiang Xinwei is an expert in telecommunications equipment from the 21st century, and he couldn't be clearer about the principle of the switch. Invented more than 100 years ago, the artificial switch has a few simple functions, such as ringing, amplifying voice signals, and conducting several channels.

With the help of electronic components such as transistors on the radio, it was a piece of cake for him as an expert. You must know that the electronic components in the radio are much more advanced and functional than the electronic components in the switch.

Moreover, in order to save time, Jiang Xinwei simplified the function again, just hoping that the circuit board he was soldering could conduct a single way.

In front of everyone's eyes, it only took about seven minutes for Jiang Xinwei to make two "circuit boards".

However, instead of using the two so-called circuit boards immediately, he silently thought for a few seconds and added a light-emitting diode and a small resistor to the first "circuit board".

When he was done, he carefully placed the two "circuit boards" on the table and looked down at the garbage-shaped switch to inspect the other circuits and components.

Soon, he finished checking it out, and a smile appeared on his face.

He turned his head to look at Deputy Mine Manager Zhang and asked, "It's not ten minutes yet?......, is it?" and it will be good right away. ”

Deputy Mine Director Zhang smiled rarely, and comforted him ideally: "Don't rush, take your time." ”

Jiang Xinwei connected the input and output pins of the two circuit boards with small wires to the corresponding parts of the switch, and then connected the DC power of the switch to the "circuit board".

Anyone who has been in a computer room knows that there is also a user patch panel before the switch is connected to the telephone. The two are connected with small wires on the patch panel, so Jiang Xinwei has small wires available here.

"It's okay!" In less than a minute, Jiang Xinwei finished welding the last pin. He clapped his hands and instructed Guo Qian, who was full of suspicion, "You use the headset on the seat to contact every phone leading to the mine." ”

"What? is it really okay?" asked Guo Qian in surprise, with an excited look on her face, "That's great." ”

She knew what the mine disaster meant to her father, and she knew what it meant to her fate. As long as the miner dies and her father goes to jail, her family will definitely fall from heaven to hell, and it will be impossible for her to do this job in this computer room that others envy.

Deputy Mine Manager Zhang was also excited, but he didn't have as much hope as Guo Qian, because he knew that even if the equipment here was normal, it didn't mean that the phone in the mine could be connected, because there was still a telephone line leading to the mine.

He looked at Jiang Xinwei silently and didn't come over to look.

Guo Qian quickly sat down in front of the seat of the artificial switch, put the headset on her head in a little panic, and anxiously picked up the plug and plugged it into the telephone jack leading to the No. 4 mine entrance.

As soon as he plugged in, Jiang Xinwei ordered: "Send a ringing signal!"

Guo Qian glanced at Jiang Xinwei, and pushed a black two-way knife throwing switch in front of the seat forward-

There was a screeching sound in the headphones, not at all like the ringing signal she was used to hearing.

Just as she was about to open her mouth to ask if the sound was a ringing signal, she saw the light-emitting diode on the paper circuit board flickering, she looked at Jiang Xinwei in puzzlement, and her eyes were obviously asking: "What does this flashing light mean?"

Jiang Xinwei frowned and ordered, "The line of this phone has been broken." Don't try it, get another one!"

Guo Qian pulled out the plug she had just plugged in and plugged in another phone leading to the No. 4 mine.

When she pushed the two-way knife throwing switch to send the ring current to the telephone, the light-emitting diode on the paper circuit board was also shining, Jiang Xinwei sighed: "The line of this phone is also broken, it is useless, try the next one!"

Guo Qian's hopeful face turned gray again, because there were only five telephones in the entire No. 4 mine: two leading to two working faces, one leading to the warehouse where the pickaxes, explosives and other materials were stored, one leading to the monitoring room for monitoring the mine's gas and other security, and one leading to the rest room when the miners changed shifts.

Now the two most dangerous work surfaces are disconnected, which means that there is an accident in the most dangerous place.

However, she still plugged the plug she had just pulled out into the phone leading to the warehouse according to Jiang Xinxu's order. Fortunately this time, when she sent the bell signal, the light-emitting diode that was staring at everyone did not flash.

"It's not bright, is the line good?" Guo Qian was secretly happy in her heart, and couldn't help but look at Deputy Mine Manager Zhang, who didn't know when to come to her.

Deputy Mine Manager Zhang was also a joy, and turned his head to look at Jiang Xinwei with Guo Qian, Zhu Jianhua and others.

What disappointed them was Jiang Xinwei sighed: "The line of this phone has been short-circuited, and it is useless, try the next one!"

Deputy Mine Director Zhang couldn't help but ask, "Short circuit?"

Jiang Xinwei did not answer his inquiry, but categorically ordered Guo Qian, who had the same doubts: "Try the next one!"

Open circuit and short circuit are both commonly used terms by electricians, the former means that the line is disconnected, and the signal is sent out by the other party and cannot be received at all. The short circuit refers to the combination of the line that sends the signal out and the line that transmits the signal back, and the signal sent out cannot reach the destination at all, so it is sent along the line back, and the other party also cannot receive the signal.

To determine whether the line is open or short-circuited is actually very simple, Jiang Xinwei can use a light-emitting diode with series resistance to achieve:

If it is an open circuit, when one line transmits the bell current signal, the other line has no signal, and the two lines have an absolute voltage difference, and the light-emitting diodes connected between the two lines naturally emit light and flash with the change of the bell current alternating current.

If it is a short circuit, because the two lines are mixed together, how the bell current signal is sent out and how to send it back, there is a small voltage difference between the two lines, and in the case of the line is not long, this voltage difference can be ignored, and the light-emitting diode will naturally not be bright.

This reason is very simple, but other people don't know the principle, so they misunderstood it, thinking that Jiang Xinwei was deliberately pretending to be a master, so that they had no confidence in the two paper circuit boards he made.

Secretary Tang couldn't bear it in his heart, and muttered in a low voice: "What kind of bullshit are you doing? The lights are on, and the lights are not on, are you hiding a woman in it, do you have to wink at you and discharge electricity into your eyes?"

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