Introduction to Microwave Diode (High Voltage) 2022

Author: Release time:2022-12-15 Source: Font: Big Middle Small View count:294

This article is mainly about the microwave diode and focuses on the microwave diode replacement and damage prevention methods for a detailed description. 

 

Ⅰ. Introduction to Diode

 

Diode, among electronic components, is a device with two electrodes, allowing current to flow only from a single direction, many of the use is the application of its rectification function. Varicap diodes, on the other hand, are used as electronically adjustable capacitors. Most diodes have a current directionality we usually call "rectification (RecTIfying)" function. The most common function of a diode is to allow current to pass in only one direction (called forward bias) and to block it when reversed (called reverse bias).

 

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The early vacuum electronic diode is an electronic device capable of conducting current in one direction. There is a PN junction with two lead terminals inside the diode, and this electronic device has unidirectional current conduction in the direction of the applied voltage. The crystal diode is a p-n junction interface made by sintering a p semiconductor and an n semiconductor. A space charge layer is formed on both sides of the interface, which constitutes a self-built electric field.

 

Early diodes included "Cat's Whisker" Crystals and vacuum tubes (known in the UK as "Thermionic Valves"). The most common diodes today use materials such as silicon or germanium.

 

1.1 Function of Diode

 

Diode is one of the most commonly used electronic components, its greatest characteristic is one-way conductivity, that is, the current can only flow from the diode in one direction.

 

The role of the diode is rectifier circuits, detector circuits, voltage regulator circuits, a variety of modulation circuits. Due to the invention of diodes and other components, there is now our rich and colorful world of electronic information birth, since the role of the diode is so great then how we should go to detect this component. 

 

In fact, it is very simple as long as the multimeter plays to the resistance file to measure the reverse resistance if very small on the diode is bad, the reverse resistance if very large which means that the diode is good. For such a basic component we should firmly grasp the principle of his role and the basic circuit, so as to lay a good foundation for future learning of electronic technology.

 

1.2 Working Principle of Diode

 


The crystal diode is a pn junction formed by a p-type semiconductor and an n-type semiconductor, which forms a space charge layer on both sides of its interface and builds a self-constructed electric field.

 

When there is no employed voltage, the diffusion present triggered by the distinction in provider focus in between both sides of the pn junction as well as the drift current triggered by the self-built electrical area are equivalent as well as in electrical equilibrium.

 

When there is an exterior onward voltage prejudice, the shared reductions of the outside electric field as well as the self-built electric area raises the carrier diffusion current and also causes the forward current. When there is a reverse voltage bias, the external electric field and self-built electric field to further strengthen the formation of a certain reverse voltage range and reverse bias voltage value.

 

When the applied reverse voltage is high to a certain extent, the electric field strength in the pn junction space charge layer reaches a critical value of the carrier multiplication process, generating a large number of electron-hole pairs, resulting in a large value of the reverse breakdown current, known as the breakdown of the diode.


Ⅱ. How to Replace a Microwave Diode

 

In all microwave circuits, there is a microwave tube to provide the anode high voltage diode, usually the same as the black and white television set on the silicon stack, is dedicated. Once damaged, it must be replaced with one of a new same type. Some consumers reflect that the same type of things in some places may not be able to buy, and is to buy, encounter poor quality, installed on the bad.

 

So troublesome to change the method there is no way to improve it? After analysis, the microwave high voltage only 1900V (AC rms), according to the peak is less than 3000 volts, and then doubled only six thousand, so, with seven 1N4007 series connection, and then set the yellow wax tube, according to the original diode position into the circuit can be.

 

After replacing the induction cooker with this method all normal, found better and cheaper than the purchase of tube, useful for consumers to say that they have been replaced for three years, has not been bad again. Repair to others have not been replaced by the bad. Suggest that friends encounter such problems, and buy the pieces of poor quality repeatedly burned, may wish to try.

 

Ⅲ. How to Test Microwave Diode

 

In the case of cutting off the power supply, remove the shell, capacitor has been discharged, the diode detection. Using a multimeter to measure the resistance of the diode, pointer multimeter "+" end (i.e., the red pen line segment, digital multimeter pen polarity just opposite to the pointer multimeter) connected to the "-" end of the diode.


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Multimeter "-" end (i.e., the black pen line end) connected to the "+" end of the diode, with a multimeter R × 10K file measured resistance should be about 100KΩ, and then the multimeter two pen pairs, the measured resistance should be infinity, it is said that this diode is normal. If the resistance measured with the multimeter in both directions is infinity or are smaller resistance, it means that the diode has been damaged and needs to be replaced.

 

Microwave diode in the use of its damage caused by numerous reasons, in the use of microwave diode and capacitors together, constituting a rectifier circuit of the microwave. It can be said that damage to the microwave diode is the most important reason for the microwave does not work properly.

 

Causes of damage to the microwave diode are, in the use of microwave due to voltage instability, when working under the wave voltage, resulting in overvoltage burnout.

 

Measure the diode good or bad, use the resistance file of the multimeter, disconnect the circuit to measure alone. Because the red bar of the multimeter through the table battery negative. So the red stick to the negative terminal of the diode, the black stick to the positive terminal of the diode, in order to conduct (pointer to low ohm). Ordinary diode, positive conduction 4 - 5k ohms, reverse resistance of a few m ohms or more, the greater the better.

 

Here the diodes work in the 4000v circuit, peak and margin considerations, higher voltage withstand requirements. This microwave diode about the store specifically for sale, the negative terminal has a ring can be connected to the base plate, the positive terminal has a set of feet can be inserted into the capacitor. The diode is easy to use. diode, in fact, there are several diodes in series, the internal resistance is high.

 

Forward resistance of about 100k ohms, reverse resistance 'infinity' diode breakdown, will burn out the fuse. diode internal burnout, there will be only AC high voltage, no DC high voltage.

 

Ⅳ. The Role of Diode in Microwave

 

1. The microwave inside two diodes, their effects are rectifier diode; maintenance effect; if the reverse voltage is too high, the diode will reverse breakdown, constituting a pathway to maintain the circuit.

 

2. The effect of rectifier diode is that when the rectifier effect diode is broken, it will blow the  fuse, diode internal burnout, only communication , no DC .

 

3. Between the anode and cathode plus - a certain DC voltage, the cathode emitted electrons by the positive potential of the anode will fly to the anode, if there is a magnet effect, there is a direction in space and the electric field straight magnetic field, electrons in the magnetic field force and electric field force effect of the pendulum movement.

 

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4. Because of the existence of high-frequency electric field in the anode resonant cavity, it will constitute the electron cloud rotating around the anode; when the rotation speed is synchronized with the high-frequency magnetic field, the electron will give all the energy to the high-frequency magnetic field, and then keep the high-frequency vibration.

 

Ⅴ. How to Prevent Damage to Microwave Diodes

 

1. In the microwave work situation must be far away, because the microwave in the work will have extremely strong radiation, the amount of use of the microwave  will bring great harm to the human body.

 

2. In the microwave diode for repair or replacement, must be a power-off state. Do not replace the microwave high voltage diode on their own, so as not to install the wrong short-circuit burned other components of the microwave.

 

3. In the inspection of non-door failure or repair microwave door switch, do not screw or remove the door switch fixing screws. This once you get down will be very troublesome, do not ask me why, a lesson learned from the past.

 

4. Regardless of the microwave that component has a problem, if you want to disassemble their own words must be very careful and cautious, may be a careful can not be installed back.

 

Conclusion

 

This is the end of the relevant introduction to microwave diodes. I hope this article will give you a deeper understanding of high-voltage diodes for microwave ovens.

 

 


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