Let's say that Li Kangping bought Baker Farm for $12,000.

There are no more cattle or sheep on the farm, leaving a house.

The wooden house was the original residence of the Baker family.

The two-story wooden house has a total area of 4,500 square feet, and the valuables were taken away by Baker, leaving some simple furniture.

Li Kangping suddenly became a land-owning family.

The apartment on Morning Street seems to be rented for nothing, but the $720 rent has been paid, so let's rent it until the end of the year. After all, it is normal for successful men to live in different districts and in different houses.

The land is already there, and the next step is to build a factory. Li Kangping sent a telegram to his father, asking his father to arrange for a few mahjong masters to come to the United States.

Li Kangping has several plans for what to do with the doctoral project, and he is waiting for the results of the Solvay meeting, and then he will judge which pure research topic to do first according to the situation.

As for the mahjong factory, Li Kangping is also waiting for Liu Shaowen's investigation conclusions and Chinese reinforcements.

Li Kangping decided to use this time to do several applied research.

He went to the electrical and hardware stores in Manhattan to buy some tools and materials, including voltmeters, amperometers, copper plates, wires, resistors, capacitors, vacuum tubes, and so on.

Li Kangping's first applied research called it: super-regenerative circuits.

Designing a housing for a super-regenerative circuit is a super-regenerative radio.

There is no such thing as a super-regenerative radio, as super-regenerative circuits have not yet been introduced.

The super-regenerative circuit, or super-regenerative radio, has an important component--- transistor.

However, the transistor has not yet been invented.

Again, this involves a purely research subject.

Before the advent of basic theories such as Fermi-Dirac statistics and quantum mechanics, it was difficult for people to make transistors in applied research.

The transistor was a revolutionary invention.

Over time, people may no longer need radios, but they can't do without transistors.

In the history of scientific and technological development, transistors were created more than 20 years after the birth of super-regenerative circuits.

Early super-regenerative circuits replaced transistors with vacuum tubes, or rather, transistors replaced vacuum tubes a few years later.

Now it is not suitable to directly invent transistors, Li Kangping uses the materials that can be obtained at this stage to devote himself to the development of super-regenerative circuits.

The ultra-regenerative circuit was developed at the Baker Farm Cabin. Oh, at this time it was changed to the planned land of the Manhattan Zeus Mahjong Factory, the temporary residence of the president.

In the 21st century, any science and engineering college student can make a super-regenerative circuit.

For Li Kangping, the job is not difficult, and he can do it alone.

Start by drawing a block diagram of the circuit principle.

Li Kangping strokes with a stroke, horizontal, vertical, horizontal, L1, C1, R3......

The super-regenerative geophone consists of a high-frequency vacuum tube, which is used to receive the signal and detect the audio signal.

The audio amplifier is composed of other vacuum tubes, and its role is to amplify the voltage and current of the audio signal output by the super-regenerative detector to drive the sound.

After the circuit schematic drawing was completed, Li Kangping started to make a super regenerative circuit.

"Let's make a high-frequency choke coil first."

Li Kangping took a resistor with a resistance value greater than 200kΩ as the skeleton, and used a wire with a diameter of 0.1mm to wrap 50 turns around the resistor, and the leads at both ends of the coil were welded to the resistors at both ends of the lead as the skeleton. Get.

Then, Li Kangping cut a 35mm×65mm copper plate, made a circuit board according to the drawing, and drilled the component mounting holes, variable capacitor fixing holes and battery clip fixing holes according to the drawing.

After doing all this work, it was already evening, Li Kangping was a little tired, he lay on the chaise longue at the door of the wooden house, drinking whiskey, smoking a cigar, looking up at the night sky, looking at the vast twelve acres of fertile fields.

The air here is fresh, the wind blows the grass and the grass is low, although there are no cattle and sheep, but it is also a place to live.

It's actually good to raise some livestock, grow some crops, be a pure farmer with nature.

However, life forced him to use this wonderful farming site to build the first mahjong factory in the United States.

The first floor of the wooden house is Li Kangping's temporary laboratory, and the second floor of the wooden house is President Li's temporary bedroom and study.

Li Kangping stayed in the wooden house, and the next morning, he had a simple breakfast, made a pot of coffee, and continued the assembly of the super-regenerative circuit.

When assembling the circuit, Li Kangping first installed the battery clip, he used a hollow copper rivet with a diameter of 2mm to rivet the positive and negative battery clips on the corresponding positions on the surface of the circuit components, and soldered the battery clip and the copper rivet and the copper rivet and the circuit board copper foil surface with solder.

Subsequently, Li Kangping installed the capacitor and coil, and he used small screws to fix the capacitor on the component surface of the circuit board, and its pins were threaded to the copper foil surface and soldered firmly. The coil is inserted into the circuit board from the component side and soldered from the copper foil side.

Then, Li Kangping soldered the power switch and the rest of the components into the circuit board one by one.

"It should be working properly, right?"

After some debugging, Li Kangping tried to use his super-regenerative circuit board to receive the signal.

Zizi.

Zizizizi.

Murmur.

A harsh murmur.

Continue debugging.

Zizi.

"President Harding...... Zizi ...... Secretary of State Hughes ...... Zizi ...... The International Affairs Conference was convened......"

"Hughes came up with a very clear plan...... Zizi ...... A ten-year naval holiday is in place, during which no large warships are allowed to be built, and all plans for large warships that have taken shape or are in the pipeline must be stopped. ”

"The navy size of the United States, Great Britain, and Japan is distributed in a ratio of 5:5:3, and the United States and Great Britain maintain the same size of the navy, while Japan can only have 3/5 of the size of the British and American ......."

The noise gradually disappeared, and the radio host's voice came to Li Kangping's ears more clearly through the headphones of the super recycled circuit board.

Succeed with flying colors!

Li Kangping clenched his fists and raised his arms in celebration.

In September 1921, after four days of procurement, drawing, assembly preparation, circuit assembly, and debugging, Li Kangping made the first super-regenerative circuit board in human history to work normally on a farm in the suburbs of New York City.

After spending another day, Li Kangping typed out the patent application documents for the super-regenerative circuit, attached a schematic diagram of the super-regenerative circuit, and then went to the patent office in New York City to apply for a patent for the super-regenerative circuit.

The patent for the super-regenerative circuit has nothing to do with Columbia University and other scientific research institutions, and this patent belongs to Li Kangping alone--- if it can be approved.

The American Patent Press is a magazine sponsored by the United States Patent Office, and you can find reports on the latest registered patents in the American Patent Journal, as well as patents registered a few years ago or more than a decade, as well as patents that have exceeded 17 years of patent protection.

Li Kangping found a few copies of the "American Patent News" and studied them carefully.

In fact, as early as 1906, before the operation of the KDKA radio station, Captains Deng Woody and Pickard of the United States Military Academy at West Point had invented the ore radio, patent number: US-749038.

Ore radio is a passive radio without amplification circuit composed of antenna, ground wire and basic tuning loop and ore as geophone, it is the simplest radio receiving device, mainly used for the reception of radio broadcasting in a strong signal environment. The older generation of radio enthusiasts almost all started with homemade ore machines.