How to measure Insulated Gate Bipolar Transistor?

( 1 ) Measure the three foot of IGBT with multimeter RX10kΩ without damping tube, one of which is infinite with the other two feet, this foot is G, and the other two feet are C and E.

In the test, there are two feet with a certain resistance, a small resistance, such as NPN type pipe, the black pen is connected to E, the red pen is connected to C; the PNP type is the opposite.

( 2 ) Measuring three electrodes with RX 10Ω ~ RX 100Ω for measuring the damping pipe. The secondary resistance is several hundred ohms, and the other one is several thousand ohms. The two feet are C and E, and the resistance is small, and the black pen is the E-pole,red stylus is the C pole, the other foot is the B pole ( G pole ).

( 3 ) When measuring and measuring IGBT module, the resistance between C-E, C-B and B-E of IGBT should be measured by using the RX 10Ω of the multimeter, which should be in accordance with the resistance of the damping pipe. If the IGBT component fails, there may be a short circuit between the collector and emitter, collector and gate. ( note : when IGBT works, the voltage between the gate and emitter is about 9V, and the emitter is the reference. If you use the road measurement method, you should first disconnect the corresponding pin, to prevent the circuit due to the impact of internal resistance caused by false judgment.

If you want to know more, our website has product specifications for the IGBTs, you can go to Allicdata Electronics Limited to get more information.

IGBT : HGTD1N120BNS9A

IGBT module : IXGN320N60A3

Transformers on the Advanced Technology Extended power board.

After opening the ATX power housing, you can observe that there are a large number of basic components and a number of chips on the ATX power board. The most striking is the appearance and volume of several transformers that are significantly different from the basic components and chips.

As the name implies, the transformer plays a voltage-changing role in the ATX process of AC/DC energy conversion.

Considering that AC market 220V is a higher voltage and that the output of each group of ATX power supplies (up to 12V and-12V at the lowest), it can be assumed that the transformer used by the ATX power supply must be a step-down transformer.

The transformer in the ATX power supply is not an ordinary transformer, but a switching transformer. As opposed to  AC transformers, AC transformers are not covered in this article.

Through disassemble a number of ATX power supplies, and the summary can be found: on any ATX power board installed with two three transformers, they vary in size, naturally should also have different functions. One of the largest, called the "main transformer" here, the other transformers are directly or indirectly to serve the main transformer.

Overall, the performance of the ATX power supply main transformer is closely related to its length (and height), as shown in figure 1.

 

Figure 1

If you want to know more, our website has product specifications for transformers, you can go to ALLICDATA ELECTRONICS LIMITED to get more information

Capacitors have those applications on the motherboard

A capacitor is a component that holds a charge and is represented by the letter C. Capacitors have the functions of charging and discharging. In mainboard circuits, capacitors are mainly used for power supply filtering, signal coupling, resonance and so on. In circuit diagrams, the capacitance is usually represented by the symbols shown in figure 1. The mainboard of the desktop uses a straight-in capacitor (see figure 2) and a chip-mounted capacitor. The direct-inserted capacitor is mostly used in the filter of power supply circuit, and the filter capacitor has positive and negative electrodes. If the positive and negative electrodes are installed, the capacitance will be damaged and the capacitor will explode seriously. The capacitor case has a white or marked one foot as a capacitor negative pole, no mark one foot as a positive pole. The common polarity of the direct capacitor is electrolytic capacitance, solid-state capacitance.

       

          （a）Nonpolar capacitance     （b）Polar capacitance

                        Fig.1 Capacitance symbo

                        

                      Fig.2 Direct-inserted capacitance

Note: when installing motherboard capacitors, the positives and negatives of the capacitors on the motherboard should be carefully measured to prevent reverse mounting. Ordinary motherboard PCB has a white shadow is negative, Asustek and Hua Qing motherboard capacitive position of the opposite, white shadow is positive at one end, should be very careful installation.

According to the appearance, the patch capacitor (see figure 3) can be divided into two types: single capacitance and row capacity. The patch capacitor is used not only for filtering, but also for coupling, resonance, voltage-up and so on.

                     

                        Fig.3 MLCC

This article is from Allicdata Electronics Limited.

Allicdata Electronic specialize in the production of safety capacitors, varistors, ceramic capacitors, film capacitors.

If you are sourcing the products, please contact us, we will try our best to solve it for you. For more product information, please go to the website to get it.

Complementary Metal Oxide Semiconductor circuit fault maintenance method.

CMOS circuit failure will lead to the motherboard can not boot, can not save CMOS settings, time is not accurate, save MOS settings after black screen and so on. These failures are caused by a drop in button battery voltage, a problem or a broken line between the button battery and the South Bridge chip, resulting in the lack of voltage in the South Bridge chip, and the fact that the 32.768kHz real-time clock crystal does not vibrate or oscillate to a standard value. CMOS jumper cap jumper misposition, etc.

1. Do not save CMOS settings for maintenance methods.

1)Measure if there is more than 2.7 V voltage on the jumper cap.

2)Check if the 32.768kHz crystal vibrates.

3)If the above conditions are normal, you can first replace the resonant capacitor and crystal oscillator.

4) Finally replace the South Bridge chip repair.

2.Time is wrong, time is fast or slow repair method.

1) Replace the 32.768kHz real-time clock crystal first.

2) It is not possible to replace the crystal oscillator, and then replace the resonant capacitor.

3)Finally replace the South Bridge chip.

3. Enter the CMOS setup program, save out of the black screen maintenance method.

1)First brush the BIOS data.

2) Writing BIOS Section can not resolve the replacement of IO chips.

3)If the above repair has not been repaired, the final replacement of the South Bridge Flower sheet.

4. The mainboard does not start the maintenance method refers to the E-board boot-up circuit of the 3rd depends on the mainboard start-up circuit CMOS causes the third step measure the main board standby condition maintenance in the method of not starting the motherboard. The maintenance method of CMOS causes the motherboard not to start according to the working principle of the starting circuit of the motherboard in Chapter 3 and the third step to measure the standby condition of the mainboard in the inspection and repair method of the starting circuit of the motherboard.

This article is from Allicdata Electronics Limited. Reprinted need to indicate the source.

What is a gas sensor and what is its function and characteristics?

1.The role of the gas sensor.

The device that can sense the change of gas sensing concentration is called gas sensor. Gas sensors are widely used in petroleum, mining, machinery, chemical and other light and heavy industries as well as ordinary families about gas poisoning and fire, detection, alarm and control of accidents such as explosion and air pollution. In industrial production and people's daily life, gas sensors are widely used to detect the leakage of combustible gases and toxic gases, in case of air pollution, explosion, fire, poisoning, etc.  There are many kinds of gas sensors , and the most common ones are semiconductor gas sensors.

2.The characteristics of the gas sensor.

Semiconductor gas sensor is the core of semiconductor gas sensor. It is made of the characteristic that the semiconductor material SnO 2 can adsorb the gas to change its resistance. When the detected gas is adsorbed on its surface, the proportion of conductive electrons in the contact interface of the semiconductor crystallite particles will change, so that the resistance value of the gas sensor will be changed measuring the concentration of the gas changes, so the gas concentration can be converted into the change of the Telecom number. This reaction is reversible and therefore reusable.

In order to speed up the reaction and achieve high sensitivity, it is usually necessary to heat the gas sensor with electric current through the heating wire. The heating temperature varies with the material used by the gas sensor. When the gas sensor starts heating in the clean air, the resistance drops sharply, and the stable value is reached after a few minutes, which is called the passive period stabilization time. When the resistance of the gas sensor is in the stable value, it will change with the adsorption of the detected gas. The variation of resistance depends on the type of semiconductor. The resistance of P-type semiconductor gas sensor increased, and the resistance of N-type semiconductor gas sensor decreased. After the gas sensor is heated, the resistance in the normal air is the static resistance Ro, and the resistance value of the gas sensor is Rx, the ratio of Ro to Rx is called the sensitivity of the gas sensor. When the gas sensor is in contact with the detected gas, the time of its resistance changing from Ro to Rx is called the response time; when the gas is removed, the time of recovery from Rx to Ro is called recovery time.

3.Choose a gas sensor in use.

(1)The sensitivity of the measured gas is high, and the variation of resistance per unit gas concentration is large.

(2) Good selectivity for single or multiple measured gases is less dependent on the temperature of the environment.

(4) Good moisture resistance.

(5) Long life.

To understand their aging mechanisms, they can predict their lifespan.

4.Detect the gas sensor.

 Add voltage to the gas sensor, when the gas sensor is connected to the circuit, the voltmeter pointer should be deflected in the negative direction and go back to zero after a few seconds, and then gradually rise to a stable value, indicating that the gas sensor has reached the preheating time. The ammeter should be indicated within 150mA, with some gas (such as alcohol, liquefied gas and so on) aiming at the gas sensitivity. Probe, use a multimeter to measure the voltage at both ends of Uo.

The gas should change, no change is bad. (the greater the amplitude of the voltmeter is, the better the performance of the gas sensor.)

If you want to know more, our website has product specifications for gas sensors, you can go to  ALLICDATA ELECTRONICS  LIMITED to get more information

Gas Sensors CCS811B-JOPD500

 LOW POWER DIGITAL SENSOR FOR INDAir Quality Sensor I²C

New superconducting materials needed to develop future computers have been discovered.

Researchers at the Karlsruhe Institute of Technology (KIT) hope to further develop future computers. This requires superconducting materials. This material has now been discovered.

Classic computers only perform one calculation step after another. Quantum computers, on the other hand, work very fast and can perform multiple computational steps simultaneously. Information carriers are so-called "qubits". They not only have the binary values "1" and "0" of the classic computer architecture, but also have values between them. This is achieved by a quantum mechanical superposition of states called superposition principles. However, it is difficult to maintain this state. Now, KIT researchers have used a quantum circuit material that retains this value longer than previously used materials: granular aluminum, or grAl for short.

Granular aluminum as a superconductor

Granular aluminum is a superconductor. These materials have no electrical resistance at very low temperatures and therefore can conduct electricity without loss. With new materials, scientists are committed to quantum computing. This is a major challenge so far. Superconducting materials are critical to maintaining the quantum state of the drill bit and joining them together. Companies such as IBM, Intel or Microsoft are already working to expand the scale of superconducting quantum processors.

High coherence time

The difficulty in maintaining the quantum state lies in the interaction with the environment, which may lead to the decline of the coherent state. The more qubits you use, the more difficult it is to maintain consistency. Granular aluminum acts as a superconductor and is known by researchers as Fluxonium qubits with a coherence time of 30 μs. During this time, more than one thousand logical operations can be performed. The researchers explained that this may increase the performance limits of previous quantum computers.

This article is from Allicdata Electronics Limited.

Comparison of advantages of OLED and QLED

The Samsung VD business unit is developing a next-generation TV roadmap that plans to skip OLEDs directly into QLEDs. “Recently, such news from the Korean media has stirred up waves and discussions in the display industry.

For Samsung's strategy, many people question QLED, which is the existing quantum dot TV on the market. It is only a technical upgrade in the LCD field, and cannot be compared with OLED. There is also a voice questioning the reason why Samsung chose QLED, which is an expedient measure after the big-screen OLED technology is unable to catch up with LG. The technical confrontation is used to disperse the market attention of OLED, and the promotion of technological progress is limited.

Such an interpretation may be one-sided. In fact, QLED, which is Samsung's next-generation display technology, is a new display technology that combines the advantages of traditional LCD and OLED.

 

As we all know, the quantum dot used by QLED is a kind of semiconductor nanocrystal. When stimulated by light or electricity, the quantum dot emits colored light. The color of the light is determined by the composition and size of the quantum dot, so it can be changed. The quantum dot morphology yields a high-peak, solid-color light that includes red to blue light, and has a congenital absolute advantage in color. The two application directions of quantum dots in the field of display technology are often confused.

The first is Quantum Dots-Backlight Unit (QD-BLU) based on quantum dot photoluminescence, which is the solution adopted by quantum dot TV on the market. The purpose is to solve the problem that the backlight of ordinary LCD TV is not enough. The problem of brightening, this color deviation is reflected in the screen image, the user will feel that the surface is cold or warm, and the best visual experience is not achieved. Using blue LEDs to obtain high-purity white light through optical materials (QDEF diaphragms) with red and green quantum dots, this problem is well solved, and at the same time, very beautiful colors are restored, which belongs to the field of quantum dots technology applied in the field of LCD. A compromise solution.

Samsung's current QLED research and development refers to the second type of quantum dot application: Quantum Dots Light Emitting Diode Display (QLED) based on electroluminescence characteristics, which belongs to quantum dot display technology. More advanced applications in the field. It is no longer that blue light produces a white light to illuminate the liquid crystal screen through a layer of quantum dot material, but is electrically driven to make the quantum dot itself emit light and produce images by color mixing, eliminating the need for liquid crystal, color film, and eliminating the backlight unit. This makes QLED and OLED have similar principles in display mode.

At the same time, QLED has several advantages over OLED:

1. Because the process is complicated, the production yield is too low has been a problem that large-screen OLED is difficult to overcome, and the QLED process is relatively simple, and has innate advantages in mass production.

2. QLED color performance is more perfect, color gamut can easily reach the most stringent color standard BT202090% or more, while OLED TV color gamut is far more than traditional LCD TV, but under the BT2020 standard, about 70%.

3. Since OLEDs use organic materials, the different lifetimes of the three luminescent materials are their insurmountable fatal injuries. The quantum dot crystal is non-organic, so the working state is more stable, the life is longer, and the cost is lower.

4. Under the same quality, the energy saving of QLED is expected to reach 2 times that of OLED screen.

Cost, production, color, energy consumption, the four major differences between QLED and OLED. In comparison, QLED is not just more "one point" than OLED. Compared with LG's struggling on the big-screen OLED, the situation is not good, Samsung seems to be a bold decision on QLED, think about it, maybe it is a good step in the chest.

Of course, QLED is still in the stage of technology research and development, and it must have some difficult problems to overcome, and it is expected that products will be available only three years later. During this period, whether OLED technology will have a leap-forward development to overcome its own shortcomings, whether QLED technology will encounter bottlenecks in development, it is hard to predict. However, as consumers return to the essence of television and pursue the quality of the face, the next generation of display technology may not be so important. It is the core of competition to provide the best display in a cost-effective form. QLED and OLED are two of the most advantageous technical disputes, leaving us with a lot of imagination space about the future display form. This is the most exciting part.