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    What is the safe operating procedure for electrical equipment commissioning?

    1. Before the test, the power switch should be disconnected and the voltage regulator should be set to zero. If a problem occurs during the test or the test is over, the voltage regulator should be returned to zero immediately and the power switch should be pulled. If a problem occurs during the test, the test can only be continued after the problem is found out.
    2. The grounding of various test equipment must be perfect, and the capacity of the grounding wire is sufficient. Test personnel should have good insulation protection measures to prevent electric shock.
    3. During the high-voltage test, the test personnel must have a clear division of labor, obey the command, and be supervised by a special person during the test.
    4. For high-voltage tests and more complex circuit tests, after the wiring is connected, it should be reviewed by the person in charge of the work. The test can only be carried out after it is correct, and a blank test should be carried out before the test object is connected.
    5. After the high voltage test, the equipment should be discharged. For equipment with larger capacitance (such as power capacitors, etc.), it must be discharged for a longer period of time. When discharging, it must first pass through the discharge resistor and then be directly grounded.
    6. When carrying out the withstand voltage test, the voltage must be raised evenly from zero, and live shock or boosting is prohibited.
    7. When performing the adjustment test, the object under test must be separated from other equipment and kept at a certain safety distance, or isolated with an insulator. When it is impossible to install fences or hang warning signs, special personnel should be assigned to guard.
    8. When working live on the secondary circuit of the current transformer, an open circuit should be strictly prevented, and a special short-circuit terminal or short-circuit piece should be used when short-circuiting, and it must be absolutely reliable. When working live on the secondary circuit of the voltage transformer, short circuit should be strictly prevented. The voltage secondary circuit must ensure that there is no short-circuit fault before it is allowed to connect to the secondary side of the voltage transformer.

    What are the main characteristic parameters of the CCD device?

    The main characteristic parameters of CCD devices include photoelectric conversion characteristics, resolution, dark current, sensitivity, etc.

    What is SPC3 memory allocation?

    Internal latches/registers are located in the first 22 bytes, which can be read or written by the user.
    Some cells are read-only or write-only, and internal working cells that are not accessible to users are also located in this area. The organizational parameters are located in units starting with 16H, and these parameters affect the use of the entire buffer area (mainly DP-SAPs).
    In addition, general parameters (station address, identification number, etc.) and status information (global control commands, etc.) are stored in these units. Consistent with the setting of the organization parameter, the User-Generated Buffer is located at the unit starting from 40H, and all buffers start at the segment address. the
    The entire RAM of SPC3 is divided into l92 segments, each segment includes 8B, and the physical address is established in multiples of 8.

    In the design, if you need to adjust the brightness of the LED, how can you achieve LED brightness adjustment?

    1. Analog regulation.
    2. Digital adjustment.
    3. Through two GPIO ports and two resistors, it is divided into 6 levels to adjust the LED brightness.

    What are the three formats of address offsets?

    • Immediate data
    • Register
    • Registers and shift constants

    How to choose a car power amplifier?

    There are many types of power amplifiers for vehicles on the market at present, and the classification methods are relatively complicated. The most common is divided into according to the way of work: A type, B type and AB type.
    Class A means that the amplifier collects the audio signal transmitted by the host at regular intervals, amplifies it and transmits it to the speaker. The “buffering effect” in this process ensures that the system can output a gentle and smooth sound signal, but the disadvantage is that it consumes a lot of energy.
    The Class B power amplifier cancels the “buffering effect” mentioned above, and the work of the amplifier is always in a timely state, but the sound quality is worse than the former.
    Class AB amplifiers are actually a combination of Class A and Class B. The conduction time of each device is between 50% and 100%. It can be called an ideal power amplifier at present.
    When purchasing a power amplifier, you must first pay attention to some of its technical indicators:

    1. Input impedance: usually indicates the anti-interference ability of the power amplifier, generally in the range of 5000-15000Ω, the larger the value, the stronger the anti-interference ability;
    2. Distortion degree: refers to the degree of distortion of the output signal compared with the input signal, the smaller the value, the better the quality, generally below 0.05%;
    3. Signal-to-noise ratio: refers to the ratio between the music signal and the noise signal in the output signal. The larger the value, the cleaner the sound.
      In addition, when purchasing a power amplifier, you must also clarify your purchase intention. If you want to add a subwoofer, it is best to buy a 5-channel power amplifier. Usually 2-channel and 4-channel speakers can only drive the front and rear speakers, and the subwoofer can only be equipped with an additional power amplifier. A 5-channel power amplifier can solve this problem. The output power of the power amplifier should also be greater than the rated power of the speaker.

    What kinds of currents can be divided according to their size and direction?

    1. A current whose direction does not change with time is called a direct current.
    2. A current whose size and direction do not change with time is called a steady current.
    3. The current whose size changes with time and whose direction does not change with time is called pulsating direct current.
    4. The current whose size and direction change with time is called alternating current.

    How can I reduce costs with the Nios II processor?

    1. Larger scale system integration
    2. Optimizing FPGA/CPU selection
    3. Better inventory management

    What are the main features of ISE?

    1. Excellent integration environment. ISE is an integrated development environment that can complete the entire FPGA/CPLD development process. ISE integrates many well-known FPGA/CPLD design tools. Reasonable application of these tools according to the design process can greatly improve product design efficiency.
    2. Simple and smooth interface style. ISE interface style is simple and smooth, easy to learn and use. The interface of ISE inherits the visual programming technology, and the interface is organized according to the design process. The entire design process only needs to click the corresponding button or select the corresponding option according to the interface organization structure.
    3. Abundant online help functions. ISE has rich online help information, combined with Xilinx’s technical support website. The problems that may be encountered in the general design process can be well resolved.
    4. Powerful design assistance functions. ISE inherits the powerful auxiliary functions of Xilinx design software. When writing code, you can use the writing wizard to generate file headers and module skeletons. You can also use language templates to help write code. The auxiliary items of ECS can be used to help design the schematic diagram during graphic input.

    PoWhat is electromagnetic induction?

    The electromagnetic induction phenomenon of inductors is “magnetic energy generating electricity” and “electric energy generating magnetism”. When a magnetic field passes through the inductive coil of a closed circuit, a current can be generated in the coil, that is, “magnetic energy generates electricity”. When a current is passed through the inductance coil, a magnetic field can be generated around the coil, that is, “electric energy generates magnetism”.


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