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  • Ten Daily Electronic Common Sense-Section 148

    What is the main reason for the mechanical lag?

    After the strain gauge is subjected to mechanical strain, there will be residual deformation inside it. A small amount of irreversible change in the sensitive gate resistance is the main cause of mechanical hysteresis.

    What are the advantages of NiosII’s implementation of embedded systems?

    1. dvantages of Configurable Soft Embedded Processors: One of the biggest challenges embedded developers face is choosing a processor that is right for their application needs. There are hundreds of embedded processors available today, each with a different set of peripherals, memory, interfaces, and performance characteristics. It is difficult for engineers to make a reasonable choice: either choose a processor that is redundant in certain performances (in order to match the peripherals and interface requirements required for practical applications, etc.), or fail to meet the original expected ideal in order to maintain cost requirements plan. With the introduction of the Nios Ⅱ soft-core processor, engineers can easily create a “perfect” processor. Whether it’s peripherals, memory interfaces, performance characteristics, and cost. These advantages are achieved by creating a custom system-on-chip on Altera’s FPGA. Or, more precisely, a SoPC. SoPC designers thus gain versatility in product features, as well as performance, cost and life-cycle advantages.
    2. Provide reasonable performance combination: Using Altera Nios Ⅱ processor and FPGA, designers can create a perfect solution in terms of processor, peripheral hardware, memory and I/O interface.
    3. Improve system performance: Embedded developers must choose a processor to determine proper system performance. Designers typically choose a higher performance processor (meaning higher cost) that has higher performance than is actually required, thereby leaving a safe performance margin. The performance of the Nios Ⅱ system can be cut according to the application, compared with fixed processors (such as ARM processors). Higher performance at lower clock rates.
    4. Reduce system cost: Embedded designers are constantly looking for ways to reduce system cost. However, choosing a processor always conflicts with cost in terms of performance and features. The end result is always at the expense of increased system cost.
    5. Coping with product lifecycles: Developers want to get their products to market quickly, maintain a long product lifecycle, and avoid replacements.

    What are the restrictions on stop mode?

    When all of the following 4 conditions are met, if the CMl0 position of the CMl register is “1” (stop mode), the microcontroller will immediately generate a low-voltage detection interrupt and return from the stop mode.
    The VC27 bit of the VCR2 register is “l” (the low voltage detection circuit is valid).
    The D40 bit of the D4INT register is “1” (low voltage detection interrupt is enabled).
    D41 bit is “1” (low voltage detection interrupt is used for return from stop mode).
    When the input voltage of the VCCl pin rises above Vdet4 (the VCl3 bit of the VCRl register is “1”). When the input voltage of the VCCl pin falls below Vdet4, it shifts to the stop mode, and when it rises above Vdet4, it returns from the stop mode. At this time, if the VCl3 bit is “0” (VCCI<Vdet4), the CMl0 position must be “1”.

    What is the complement/reverse command?

    H: X/SP increase instruction AIX/AIS is used for 16-bit index register.
    H: The value in X or the 16-bit stack pointer SP is directly increased by an 8-bit signed immediate value. The range that can be represented by 8-bit signed number is -l28~127, and the parameters beyond this range will be regarded as illegal by the compiling software.

    What is the role of the phosphorescent photosensitizer?

    The role of the phosphorescent sensitizer is to make the triplet excitons transfer energy to the fluorescent working substance, so that all the energy can be effectively used. Thereby reducing the consumption of some energy in the device.
    This is a relatively special and novel subject-object structure. It not only utilizes the high efficiency of fluorescent dyes, but also overcomes some disadvantages of phosphorescent dyes.

    Why do capacitor applications have to be accompanied by Resistorss?

    A capacitor is an energy storage element that, when connected to a voltage source, charges up to the source’s highest voltage and stores the charge for the capacitor’s rated capacity. Thus, in the case of a fault, when a low-resistance path appears between the two ends of the capacitor, the current given in the low-resistance path is =V/R. When R>-0, the capacitor will work as a power supply.
    In this case, a very high current flow occurs for a very short time (depending on the energy stored in the capacitor). Such a large current could cause sparks around it, which could lead to ignition in the atmosphere.
    Therefore, it is clear from the above discussion that there must be a current limiting resistor (CLR) in series with the capacitor. Thereby, the ignition current at a certain voltage specified by the intrinsic safety standard may not be violated.
    The resistance value connected to the capacitor is selected as follows: R=voltage applied across the capacitor/minimum current required for ignition at this specific voltage

    What are the important technical indicators of the successive approximation analog-to-digital converter?

    1. Resolution: That is, the A/D conversion accuracy, which mainly depends on the minimum quantization unit of the set digit. The more digital quantity digits output by A/D, the smaller the minimum quantization unit. The higher the resolution, the smaller the rounding error of the converted digital quantity, and the higher the A/D conversion accuracy.
    2. A/D conversion speed: refers to the time required for the analog-to-digital converter to convert the analog quantity into a digital quantity once. Usually the higher the resolution, the lower the conversion speed. If the resolution and conversion speed are required to be high, the cost of the chip is very expensive.
    3. Principle of digital-to-analog converter (DAC): The function of the digital-to-analog converter is to convert the digital quantity into a corresponding analog voltage quantity output through the decoding circuit. The size of the digital quantity is represented by the bit weight combination of the binary number. The size of each bit whose digital quantity is l is the weight of the bit. Adding all the bit weights of 1 by weight represents the size of this digital quantity.

    What are the two principles of oscillation blocking?

    The first consists of a four-part criterion.
    The second is to distinguish between short circuit and oscillation according to the rate of change of the impedance resistance component measured at the installation place of the protection device.

    What is a small-scale propagation model?

    The small-scale propagation model is used to describe the rapid changes of the wireless signal after a short period of time (or a short distance). Such variations include amplitude, phase, frequency, and delays caused by multiple paths. Because this type of model is to observe signal changes within a short time or distance.
    Therefore, the power impact caused by large-scale propagation can be ignored. In small-scale propagation models, the strength of a signal can vary hundreds or thousands of times in just a few milliseconds.

    What is the detection method for the throttle position sensor of the Audi 200?

    • Turn on the ignition switch, check the voltage of the power supply terminal of the connector with a multimeter on the harness side, and the voltage is the battery voltage.
    • Turn off the ignition switch, unplug the throttle wire harness connector, and use a multimeter to check the continuity of the relevant terminals. When the idle speed switch is closed, that is, when the idle speed contact is connected, the signal terminal of the idle speed switch and the intermediate terminal should be conducted. When the idle switch is turned on, that is, when the idle contact is disconnected, the signal terminal of the idle switch and the middle terminal should not conduct. When the throttle opening is less than 570, the heavy load switch is turned on. That is, when the contact of the heavy load switch is disconnected, there should be no conduction between the signal terminal of the heavy load switch and the intermediate terminal. When the throttle opening is greater than 570, the heavy load switch is closed. That is, when the contact of the heavy load switch is connected, the signal terminal of the heavy load switch and the intermediate terminal should be conducted.


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