Ten Daily Electronic Common Sense-Section 35

What are the main performance indicators of the device HA22004P?

1. Input voltage range: 85～240VAC.
2. Constant current range: 10 ~ 40mA (external adjustment).
3. Temperature range: -40～85℃.
4. Accuracy: 5%, -10% (negative temperature coefficient).
5. Adaptation range: ∑UF≤0.9UINDC, UF is the working voltage of each LED.
6. Package: DIP-8 or DIP-14 (NA20003P with DIP-14 package has group control and level control switch functions).
7. Good stability, high cost performance, and a wide voltage and temperature curve. Figure 3-22 shows the typical temperature curve of HA22004P (regulating current is 20mA).
8. The parameters are stable within the working range; the EMC characteristics are good.

What is the detection method for the three-phase solid-state voltage regulating relay?

Similar to the detection of ordinary relays, that is, according to the wiring diagram and nameplate, add a suitable voltage to the input terminal. Adopt voltage regulation measures, and then use the AC voltage block of a multimeter to detect whether the output voltage can change. If yes, it means that the voltage regulating relay is normal.

What are the main differences between timing analysis and state analysis?

The main difference between timing analysis and state analysis is: timing analysis is controlled by the internal clock sampling, and the sampling is asynchronous with the system under test; state analysis is controlled by the clock of the system under test, and the sampling is synchronous with the system under test.
Use timing analysis to see “when” events occur, and state analysis to check “what” events occur. Timing analysis usually displays data in waveforms, and state analysis usually displays data in lists.

What is a reader?

Readers, also known as readers (depending on whether the data in the electronic tags can be rewritten), programmers, etc., are devices that read and write electronic tag information.
The reader is a very important part of the RFID system. On the one hand, the weak electromagnetic signal returned by the electronic tag enters the radio frequency module of the reader wirelessly and converts it into a digital signal, which is then processed and stored by the logic processing unit to complete the identification or read-write operation of the electronic tag. On the other hand, the upper-layer software and the reader need to interact to realize the execution of operation instructions and the summary upload of data.
Under normal circumstances, radio frequency tag reading and writing equipment should be designed according to the reading and writing requirements and application requirements of radio frequency tags. With the development of radio frequency identification technology, radio frequency tag reading and writing equipment has formed some typical implementation modes. The future readers will show the trend of intelligence, miniaturization and integration, and will also have powerful front-end control functions. In the Internet of Things, the reader will become the core device with communication, control and computing functions at the same time.

What are the reasons for the zero residual voltage?

• Fundamental component
• High-order harmonics

What is the difference between the Mealy state machine and the Moore state machine?

First, the output of the Mealy state machine is directly affected by the input, so input changes can occur at any point in the clock cycle. The output of the Moore state machine is only determined by the current state, so the output is stable within one clock cycle, except that the output may be unstable within a few gate delay times after the rising edge of the clock.
Second, to achieve the same function, the Moore state machine requires more states than the Mealy state machine.

Briefly describe Hebb theory and STDP learning mechanism：

Hebb’s theory describes the basic principle of synaptic plasticity, that is, continuous and repeated stimulation of presynaptic neurons to postsynaptic neurons can lead to an increase in synaptic transmission efficiency, proposed by Hebb in 1949.
Based on this theory, Henry Markram proposed a spike timing dependent plasticity (STDP) learning method. It adjusts the strength of connections between neurons according to the order in which neurons learn.  
STDP can be said to be an extension of Hebb’s theory. Hebb proposed that if two neurons often act together, the synaptic connection between them will be strengthened. STDP further perfects this theory, the activity of two neurons, if the stimulation of the presynaptic membrane is earlier than that of the postsynaptic membrane, will cause long-term potentiation (LTP) of the synapse; otherwise Synaptic long-term depression (LTD) is induced.
STDP rule is an important learning rule in artificial neural network. The simulation of neural synapse learning function generally needs to be realized by STDP rule.

What is the difference and connection between active and passive devices?

The most basic components of passive devices are passive components, and there will be no active components. The functions of passive devices in the indoor sub-system include signal transmission (such as feeder), power distribution (such as power divider, coupler), and signal amplification (such as antenna) by focusing the transmission direction of the signal.  
The core components of active devices are active components, and of course passive components are also required. Active devices are generally used for power amplification (such as repeaters, dry amplifiers), signal conversion (such as signal sources) and so on. All functions of wireless signal conversion, such as oscillation, amplification, modulation, demodulation and other functions, are inseparable from active components, so active components are the core components of the signal source.

What constitutes the structure of a short frame?

It consists of start bit S, 7-bit data bits bl-b7 and communication end bit E.

What is iron powder?

Iron fine powder is also called iron powder. Iron ore (ore containing iron element or iron compound) is processed into ore powder called iron fine powder after crushing, grinding and beneficiation.
In theory, any ore containing iron or iron compounds can be called iron ore. However, in terms of industry or commerce, iron ore must not only contain iron, but must also have value for use. 
Iron exists in nature in the form of a compound, especially in the form of iron oxide in a particularly large amount.
Now, several more important iron ores will be put forward to illustrate: (1) Magnetite (Magnetite): It is an ore of iron oxide. The main component is Fe3O4, which is a composite of Fe2O3 and FeO, with a dark gray color, a specific gravity of about 5.15, containing Fe72.4%, O27.6%, and has magnetic properties. Magnetic separation can be used in beneficiation, which is very convenient to handle; however, due to its fine structure, it has poor reducibility. After long-term weathering, it becomes hematite. (2) Hematite: It is also an iron oxide ore. The main component is Fe2O3, which is dark red, with a specific gravity of about 5.26, containing Fe70% and O30%. It is the most important iron ore. According to its own structure, it can be divided into many categories, such as Redhematite, Specularhematite, Micaceoushematite, and RedOcher. (3) Limonite: This is an ore containing iron hydroxide. It is the general name of two different structure minerals, Goethite HFeO2 and Lepidocrocite FeO (OH). Some people also write the chemical formula of its main components as mFe2O3. nH2O, showing natural yellow or brown color, contains Fe about 62%, O27%, H2O11%, and the specific gravity is about 3.6 to 4.0, most of which are attached to other iron ores. (4) Siderite: It is an ore containing iron carbonate. The main component is FeCO3, which is blue-gray and has a specific gravity of about 3.8. Most of this ore contains considerable amounts of calcium and magnesium salts. Since carbonate will absorb a lot of heat and release carbon dioxide at a high temperature of about 800 to 900 ° C, we usually roast this type of ore first and then add it to the blast furnace. (5) Iron silicate ore (SilicateIron): This type of ore is a compound salt without a certain chemical formula. The composition changes greatly. Generally, it is dark green, with a specific gravity of about 3.8. The iron content is very low. A poor iron ore. (6) Sulphideiron: This ore contains FeS2, only 46.6% Fe and 53.4% ​​S. It is grayish-yellow, and its specific gravity is about 4.95 to 5.10. Because this ore often contains many other more precious metals such as copper (Copper), nickel (Nickel), zinc (Zinc), gold (Gold), silver (Silver), etc., it is often used as a metal smelting industry. raw material; and because it contains a lot of sulfur, it is often used to extract sulfur, but iron becomes a by-product, so it can no longer be called iron ore. 
Iron ore origin: (1) Domestic: The distribution of iron ore in my country is mainly concentrated in Liaoning, Sichuan, Hebei, Beijing, Shanxi, Inner Mongolia, Shandong, Henan, Hubei, Yunnan, Anhui, etc., Jilin, Heilongjiang, Shanghai, Jiangsu, Zhejiang, 29 provinces, municipalities and autonomous regions including Fujian, Jiangxi, Hunan, Guangdong, Guangxi, Hainan, Guizhou, Tibet, Shaanxi, Gansu, Qinghai, Ningxia and Xinjiang. (2) Abroad: The world’s iron ore resources are concentrated in Australia, Brazil, Russia, Ukraine, Kazakhstan, India, the United States, Canada, South Africa and other countries.