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  • Ten Daily Electronic Common Sense-Section 49

    What is a multi-rack link aggregation or a cross-stack Ethernet channel?

    A multi-rack LAG terminates interfaces on two different nodes. This is an implementation with higher availability, as the LAG can withstand failure of the connection target. Each vendor has specific implementation details, and you should be aware of the existence of MC-LAG. It is more robust because the failure of a single switch target does not mean the loss of the aggregated link. Specific examples include Virtual Port Channel (Cisco) and Distributed Backbone (HP).

    What are the characteristics of the S3C2440A timer?

    Five 16-bit timers; two 8-bit prescalers and two 4-bit frequency dividers; PWM waveform output with programmable duty cycle; auto-reload mode or one-shot pulse mode; dead-band generator.

    What kinds of modules are programmable colorful neon lights?

    The programmable colorful neon lights are divided into five modules, including two frequency divider modules, RAM memory module, display module and key control module.

    What are the identification methods for commonly used Zener diodes?

    • Zener diodes are often represented by “ZD” plus numbers in the circuit, such as: ZD5 represents the Zener tube numbered 5.
      • The voltage regulation principle of the Zener diode: The characteristic of the Zener diode is that after breakdown, the voltage across its terminals remains basically unchanged. In this way, when the voltage regulator tube is connected to the circuit, if the power supply voltage fluctuates. When the voltage of each point in the circuit changes due to other reasons, the voltage across the load will remain basically unchanged.
      • Fault characteristics: The fault of the Zener diode is mainly manifested in open circuit, short circuit and unstable voltage regulation value. Among these three kinds of faults, the former fault shows that the power supply voltage rises; the latter two faults show that the power supply voltage drops to zero volts or the output is unstable. The models and voltage regulator values of commonly used Zener diodes are as follows: Model1N47281N47291N47301N47321N47331N47341N47351N47441N47501N4751

    How to set the DC Master communication area?

    Select DC MASTER in the hardware configuration window, open the folder “MASTERDRIVES/DC MASTER CBP2 DPV1”, drag and drop “PP01: 4 PKW, 2 PZD” to the window below the figure.
    Line 1 is PKW and line 2 is PZD. Double-click the 1st line, in the “Address/ID” tab of the DP slave station properties dialog box that appears, change the starting address of the output and input of the PKW to 52. Double click on line 2 and change the starting address of the output and input of the PZD to 60. Note that the above address area cannot overlap with the input and output address areas of the master station and other slave stations.  
    What DC MASTER transmits is consistent data, the master station needs to call SFC 14 and SFC 15 to pack and send the data, and unpack the received data.

    What are the three types of sampling data circuits?

    At present, there are three types of sampling data circuits: a circuit composed of a charge-coupled device (CCD), a switched-capacitor circuit (Sc) and a switched-current circuit (SI).

    What are the main features of the MAXl773/MAXl773A power-selector chip?

    1. Adopt 7-MOSFET topology patent technology to reduce system cost.
    2. It can automatically detect and respond to low power supply voltage, battery insertion and removal, and AC adapter connection and disconnection.
    3. It can directly drive P-channel MOSFET.
    4. With a simplified power management microprocessor.
    5. Allows the power management microprocessor to enter standby mode, thereby extending battery life.
    6. The input voltage range of AC adapter is 4.75~28V.
    7. Contains LD0 with 1mA drive capability.
    8. Adopt small size 20-pin TSSOP package.

    What is the inverse piezoelectric effect or electrostrictive effect?

    When an electric field is applied in the polarization direction of certain substances, these substances will produce mechanical deformation; when the applied electric field is removed, the mechanical deformation of these substances will disappear. This phenomenon of converting electrical energy into mechanical energy is called the inverse piezoelectric effect or electrostrictive effect.

    What are the LDM and STM command modes?

    • There are 8 “modes” as follows (the first 4 are used for data block transfer, and the last 4 are stack operations):
      1. IA adds 4 to the address after each transfer;
      2. IB adds 4 to the address before each transfer;
      3. DA increases the address after each transfer Decrement 4;
      4. DB decrease the address by 4 before each transfer;
      5. FD full decrement stack;
      6. ED empty decrement stack;
      7. FA full increment stack;
      8. EA empty increment stack.

    What is self-inductance and self-inductance?

    Self-inductance – When the current in the closed loop changes, the magnetic flux through the loop itself generated by this current also changes. Therefore an electromotive force will also be induced in the loop. This phenomenon is called self-induction phenomenon, and this induced electromotive force is called self-induced electromotive force.


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