What does magnetron mean? What does the controller mean by magnetic weakness

Utilize electromagnets.

to control the device. The magnetron usually operates in mode, and the phase of the microwave electric field at the cavities of the two adjacent resonators is exactly 180°, that is, the microwave electric field is exactly opposite (Figure 2). Although this microwave field is a standing wave field, in the case of modulus, it is equivalent to two identical microwave fields moving in opposite directions on the circumference, and the phase velocity values of the two fields are equal.

The electrons emitted from the cathode are in an orthogonal electromagnetic field.

Under the action of the cycloid.

Motion. The DC voltage and the constant magnetic field are adjusted so that the average drift velocity of electrons in the circumferential direction v=e b is exactly equal to the phase velocity v of a microwave field moving in its direction (where e is the average value of the DC electric field generated by the DC voltage in the interaction space.

b is the axial constant magnetic induction intensity, so that the electrons can move synchronously with the microwave field. During the synchronous motion, the part of the electrons in the microwave deceleration field gradually gives its DC potential energy to the microwave field, moves closer to the anode, and finally collects it by the anode. This part of the electrons transfers energy to the microwave field, which is conducive to the establishment of stable microwave oscillations in the magnetron, so it is called favorable electrons.

The part of the electrons that are in the microwave acceleration field gets energy from the microwave field and moves towards the cathode, and finally hits the cathode. This part of the electrons is called the unfavorable electrons. The unfavorable electrons shoot a large number of secondary electrons when they return to the cathode, so that the number of electrons in the interacting space increases.

The maximum deceleration field is the center of electron clustering. The electrons on both sides of it are moved towards the center of the group by the force that moves closer to the center of the group. The maximum acceleration field is the center of electron dispersion, and the nearby electrons are subjected to the force of the discrete center and move to the left and right respectively, which is converted into favorable electrons.

In this way, in the process of oscillation, there are fewer and fewer unfavorable electrons, and more and more favorable electrons, which are concentrated in the cluster center, and gradually form a spoke-like electron cloud in the interaction space. This phenomenon of electrons in different phases automatically clustering into a spoke-like electron cloud in the interaction space is called automatic phase focusing. The microwave field in the interaction space decays exponentially as it moves away from the anode surface.

Therefore, the microwave field on the surface of the cathode is extremely weak, the swarming effect on electrons is minimal, and there is no obvious electron spokes formed near the cathode, but an almost uniform distribution.

of electronic wheels.

The favorable electrons account for the vast majority of the electrons in the interaction space, and they all have a long rotation time in the process of moving towards the anode, and they can fully rotate the DC potential energy into microwave energy. There are fewer electrons that bounce back at the cathode, and they hit the cathode shortly after being emitted from the cathode, so they absorb less energy from the microwave field. In this way, the overall effect of the interaction between all the electrons in the interaction space and the microwave field is that the electrons hand over the DC potential energy to the microwave field, and a stable microwave oscillation is established in the magnetron.

Electromagnetism controls the path of ion movement, such as magnetron sputtering coatings.

The current magnetized core changes the conductivity and changes the inductive reactance.

A weak field controller refers to a method of controlling a motor, in which the current is changed in a way that can control the operating state of the motor. This controller can have a significant impact on the speed, steering and position of the motor. Normally, the weak field stool controller will change the state of the motor by reducing the current or changing the direction of the current, so as to achieve the ideal control effect.

In addition, when the motor starts running, the weak field controller can ensure that the speed of the motor gradually increases, so that it accelerates smoothly from a standstill. The slow acceleration process provided by this controller extends the life of the motor and reduces the mechanical stress that occurs due to sudden start-ups. Due to the advantages of this slow acceleration, weak field controllers are often used in industrial applications and machine control.

Another important advantage of the field weakening controller is that it can provide dynamic braking for the motor. When the motor is required to stop, the controller can slow down the motor until it stops, reducing the risk of mechanical stress and damage caused by braking, and also improving work safety. In addition to this, the weak field controller can also adjust the motor output power to change the speed and steering characteristics of the motor.

This quick adjustment makes it ideal for automated processes, such as automated factory assembly lines.

In short, the weak field controller can realize the efficient management of the motor through the control characteristics such as current control, slow acceleration and targeted braking, so that the motor can be widely used in various fields such as industrial and machine control. <>

When the speed of the motor exceeds a certain value, the excitation current has been small, and it can no longer be adjusted, and it enters the stage of weak field control.

The concept of weak magnetism comes from the control of direct current transmission, and the phenomenon of weak magnetism is a variety of phenomena manifested by the material before the weak magnetic core, and the weak field science is a discipline that studies the phenomenon, nature, law and application of the weak magnetic field of matter, and is a branch of magnetism. Modern science and technology have revealed that all matter is magnetic, and there is a magnetic field in any space.

The concept of weak magnetic speed regulation:

1. In the theory of DC motor, the methods of changing the speed of DC motor are: changing the armature voltage speed regulation, and reducing the excitation current and weakening the main pole magnetic flux speed regulation.

2. In the speed regulation of the inverter to the asynchronous motor, when the output frequency of the inverter is higher than the rated frequency of the motor, the magnetic flux of the motor core begins to weaken, and the motor speed is higher than the rated speed.

3. When the inverter regulates the speed of the asynchronous motor, once it enters the weak magnetic field speed regulation, the inverter will not change the output voltage of the inverter, which is generally the rated voltage of the motor. The motor current increases, exceeds the rated current, the electromagnetic torque decreases when the speed increases, and the motor power is constant power, so some people call the weak magnetic speed regulation also called constant power speed regulation. <>

The microwave multi-function instrument uses the thermal effect of microwave biological tissues to stop bleeding, coagulation, cauterization or anti-inflammatory, reduce swelling, relieve pain, and improve blood circulation in local tissues to achieve the effect of disease. A magnetron is an electrical vacuum device used to generate microwave energy. Magnetron is a consumable that is prone to aging and demagnetization after frequent operation.

A magnetron is an electrical vacuum device used to generate microwave energy. It is essentially a diode placed in a constant magnetic field. Under the control of the constant magnetic field and the constant electric field perpendicular to each other, the electrons in the tube interact with the high-frequency electromagnetic field to convert the energy obtained from the constant electric field into microwave energy, so as to achieve the purpose of generating microwave energy.

At the same time, magnetron is a consumable that is prone to aging and demagnetization.

The magnetron is an important component used to generate microwaves in the microwave instrument. A constant magnetic field is required to generate microwaves, so there is a ring-shaped permanent magnet inside the magnetron. We want the magnet to maintain a constant magnetic force at all times, but there are various factors that may cause the magnetic force of the magnet inside the magnetron to fade (degauss), such as high temperatures and strong magnetic environments.

Wait. Generally speaking, the decline in the performance of the magnetron is mostly caused by the aging of the filament inside, and rarely caused by the degaussing of the magnet.

It may have been in contact with iron or rubbing. deformed.

How a magnetron works.

<> magnetron, which can be divided into pulse magnetron and continuous wave magnetron according to the working state; According to the structural characteristics, it can be divided into ordinary magnetron, coaxial magnetron and anti-microwave magnetron.

Microwave magnetron.

shaft magnetron; According to the frequency adjustable or not, it can be divided into fixed frequency magnetron and frequency adjustable magnetron. Frequency-adjustable magnetrons can be further divided into mechanically tuned magnetrons and frequency-agile magnetrons. There is also a type of voltage-tuned magnetron that achieves frequency tuning by changing the anode voltage.

The operating pulse width of the pulsed magnetron can vary in the microsecond range, the operating frequency range is between 250 MHz and 120 GHz, the pulse power is from tens of watts to tens of megawatts, the efficiency can reach 70%, and the life can reach tens of thousands of hours. Pulsed magnetrons are widely used in various radars such as guidance, fire control, altimetry, airborne, shipborne, meteorology, etc.

Continuous-wave magnetrons are used in electronic countermeasures, industrial heating, and microwave physiotherapy. Inexpensive continuous-wave magnetrons with a power of between 400 and 1000 watts are also widely used in household microwave cookers. In order not to interfere with the normal operation of radar and communication equipment, the frequency of the magnetron used in medical, industrial heating and cooking is usually 915 25 MHz and 2450 50 MHz.

Frequency-adjustable magnetrons, especially frequency-agile magnetrons, can improve the anti-jamming ability of radar.

Continuous-wave magnetron.

Voltage-tuned magnetrons are often used as a power source for electronic countermeasures equipment, which can be used to supply CW power from a few watts to several hundred watts. It has the advantages of fast tuning speed and good tuning linearity. The tuning range of the low-power voltage tuned magnetron can reach 2:

1, 4: 1, or even 20: 1, can greatly improve the electronic countermeasure capabilities of various radars.

Its main disadvantage is that the output power is not large enough to be used for electronic countermeasures of radar elimination.

Magnetism: Substances have the property of attracting metals such as iron, cobalt, and nickel. Magnet: An object that has magnetic properties.