My IQ has been increasing year by year.

A hoarse voice sounded behind Chen Zhuo.

Immediately following was a crisp "click" sound from a lighter.

A cluster of orange flames lit up in the darkness, illuminating a face covered in stubble, with deep eye bags, and hair as messy as a bird's nest.

Old Zhou.

Zhou Guoping, head of the physics teaching and research group at the No. 1 Middle School of the city.

A strange old man who, in the eyes of his students, always wore ill-fitting jackets, reeked of cigarettes, and would often veer off-topic into quantum mechanics during his lectures.

Old Zhou, with a cigarette dangling from his lips, took a deep breath, the embers flickering in the dark laboratory.

He wasn't angry about catching a student messing around in the lab.

Instead, his eyes, which were usually half-closed, were now fixed on the oscilloscope screen with great interest.

"The signal generator of J2459 is an analog circuit, which is greatly affected by temperature."

Old Zhou exhaled a smoke ring, the smoke swirling in front of the green fluorescent light, adding a hazy filter to the ghostly waveform.

"It's hard to lock high-order harmonics with this kind of broken machine. If you can stabilize that three-node Lissajous figure, even if you only stabilize it for two seconds, the feel is pretty good."

Chen Zhuo turned around and got off the round stool.

"Teacher Zhou."

Old Zhou waved his hand, took a cigarette, and walked to the lab bench.

He didn't turn on the light either.

The two people were like two bats accustomed to the darkness, facing off in this room filled with the smell of electronics.

"What was the frequency of that '8' just now?" Old Zhou suddenly asked.

"1:2," Chen Zhuo replied.

"What about the crown?"

3:4

Old Zhou raised an eyebrow.

Using the light from the oscilloscope, he looked down at the short man who only reached his waist.

He remembered this child.

That left a deep impression on me.

That madman who drew a force analysis diagram of a wheel on his entrance exam paper.

The student who skipped a grade and was given a spare key to the lab despite not meeting the usual requirements.

But he didn't expect the child to actually come.

And they're playing such wild things on their first visit.

When an average junior high school student enters a laboratory, they either want to touch a balance scale or look at a microscope.

Only a real freak would hide in the dark playing with some crappy oscilloscope.

"Will it be able to be rounded?"

Old Zhou suddenly reached out and twisted the oscilloscope knob hard a few times.

The originally somewhat regular waveform was instantly and completely disrupted, turning into a diagonal line devoid of any aesthetic appeal.

"Round?" Chen Zhuo was taken aback.

"Yes, round."

Old Zhou pointed to the screen.

"The Lissajous figure, the simplest yet most difficult to manipulate, is a circle."

"To draw a perfect circle, the frequencies of the two channels must be exactly equal, a 1:1 ratio. And..."

"The phase difference is exactly 90°, which is π/2."

"A little more, and it's an ellipse. A little less, and it's still an ellipse. If the frequency is slightly unstable, the circle will spin in circles."

"Make me a circle. If you can't, give me back the key."

Old Zhou took a deep drag on his cigarette and quietly watched Chen Zhuo.

This is a challenge.

Or perhaps, this was a genuine qualification review of this "genius" by Lao Zhou, the physics group leader.

Being able to solve problems is nothing special.

Physics, in essence, is the science of experimentation.

If your hands tremble in front of real instruments, you're nothing more than a Zhao Kuo who only knew how to talk about war on paper.

Chen Zhuo looked at Lao Zhou's face, which was faintly visible behind the smoke.

He didn't speak.

He turned around and sat back down on the round stool.

Adjust to a round shape.

In mathematics, this is simply an equation:

x² + y² = r².

But in the world of analog circuits, this is incredibly exciting.

Chen Zhuo took a deep breath.

His hand rested on the knob again.

The first step is frequency synchronization.

He slowly adjusted the frequency of the signal generator back to 50Hz.

The light spots on the screen started to draw circles, but they weren't circles; instead, they were a constantly rolling ellipse, tilting left and right.

This means that the frequency is not completely locked.

Chen Zhuo closed his eyes, feeling the stiff meshing of the gears inside the knob.

Left fine adjustment.

Make a slight adjustment to the right.

stop.

The rolling stopped.

A stable slanted ellipse appeared on the screen.

This image now means the frequency ratio is locked at 1:1.

Next, we come to the phase.

The current phase difference is about 45 degrees, so it is an slanted ellipse.

To expand this ellipse into a full, perfect circle, phase adjustment is required.

However, this old J2459 oscilloscope does not have a separate phase adjustment knob.

What should I do?

Old Zhou stood to the side, a mocking smile on his lips.

He knew about the defects in this broken machine.

Without an external phase shifter, it is almost impossible to achieve a perfect circle.

He was deliberately making things difficult for this kid.

But the next second, Lao Zhou's lips froze.

Chen Zhuo did not touch the knob.

He stood up and walked behind the instrument.

Chen Zhuo stretched out two slender fingers and pinched the wire that connected to the signal generator.

Then, he started to knead.

There was no force applied; the bending of the wire was simply changed gently, almost as if the temperature of the fingers was being used to heat the wire.

wrong.

Old Zhou squinted his eyes.

He wasn't pinching the wire.

He was touching a capacitor.

Chen Zhuo's fingers rested on a variable capacitor knob at the output of the signal generator. The plastic cover of the knob had long since fallen off, leaving only a bare metal rod, which was very inconspicuous.

But that's where you adjust the time constant of the RC circuit.

That is, the place where the phase is adjusted.

Chen Zhuo stared at the screen.

His fingers gently turned the metal rod.

The amplitude of that rotation was so small that it was almost invisible.

The slanted oval on the screen suddenly started to slowly get fatter.

It's like a balloon being inflated, starting to swell little by little.

Chen Zhuo's breathing seemed to stop.

All that remained in his eyes was that green light.

Nearly.

closer.

At that very moment, the major and minor axes of the ellipse reach a visually perfect equality.

Chen Zhuo's fingers loosened.

hum~

On the screen, a faint green light stretched out from one end to the other, curving into a perfect arc.

It hovered silently behind the dark glass.

Not flat.

Not sharp.

It does not rotate.

It's like a green halo floating in the vacuum of space.

A perfect circle.

Phase difference Π/2.

The frequency ratio is 1:1.

Time seemed to freeze at that moment.

Old Zhou's fingers, holding a cigarette, hovered in mid-air, a long ash piled up, teetering precariously.

He looked at the circle, the playfulness in his eyes vanished, replaced by an almost greedy appreciation.

An expert can tell a lot just by looking at their work.

It's remarkable that such a stable phase could be achieved on this old, poorly connected device by blindly adjusting the capacitor with a tactile feel.

This cannot be explained by the word "smart".

That's talent.

It is an absolute intuition about the microsecond-level changes in electron flow.

This kid was born for this.

"Smack."

Old Zhou's long cigarette ash finally fell off and landed on his leather shoes.

He snapped out of his daze, threw the cigarette butt on the ground, and stomped it out.

"Alright."

Old Zhou's voice was still hoarse, but his condescending examiner attitude had completely disappeared.

"Shut down the computer."

Chen Zhuo obediently turned off the power.

The perfect green ring shrank to a single point in an instant, and then slowly disappeared into the darkness.

The laboratory was plunged into darkness once again.

Old Zhou turned and walked towards the door.

He stopped at the door and glanced back at Chen Zhuo, who was still packing his schoolbag.

"Don't play this machine anymore."

Old Zhou pointed disdainfully to the J2459 that had just made great contributions.

"The potentiometers here are almost oxidized. They're only good for practicing your feel for the waveforms. They're for those silly eighth graders to look at."

After saying that, he took out a key from his pocket and made a rattling sound.

He picked one of them off; it was noticeably newer than the previous one, and the gears were much more complex.

"then."

In the darkness, a metallic parabola streaked across the sky.

Chen Zhuo raised his hand and caught it steadily.

"In my room in the physics teaching and research group, a Japanese Kikusui dual-track oscilloscope with a bandwidth of 20 MHz was just delivered, along with a signal generator that can output triangular and square waves."

Old Zhou opened the door, and the dim light in the corridor illuminated his back.

"If you don't want to go to evening self-study in the future, come to my room and play. Don't stay here and collect dust."

"besides."

Old Zhou paused, as if he had remembered something.

"There's a preliminary round for the National Junior High School Applied Physics Knowledge Competition next March. I've put a set of papers on your desk. Do them when you have time, or don't bother if you don't. I'm not expecting you to win any awards anyway, it's just to make up the numbers."

After saying that, Old Zhou waved his hand and left without looking back.