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LM358: Function of LM358 in circuit inverter

Part Number: LM358

I don't understand function of LM358 in circuit inverter ( attch)

  • Edit schematic

  • In reply to Lai Hai:

    Lai,

    LM358 is a unity gain buffer for the signal applied to its non-inverting input.

    Regards,
    Ronald Michallick
    Linear Applications

    TI assumes no liability for applications assistance or customer product design. Customer is fully responsible for all design decisions and engineering with regard to its products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning Customer's design. If Customer desires engineering services, the Customer should rely on its retained employees and consultants and/or procure engineering services from a licensed professional engineer (LPE).

     

  • In reply to Ron Michallick:

    Thanks you!
  • In reply to Lai Hai:

    Hi Lai,

    from where is this schematic? Have you a link?

    In the first schematic LM358 and LM324 seem to be part of a PID.

    In the second schematic circuitry at input of LM358 looks strange. Shall this be an input bias current cancelation? Strange...

    Kai
  • In reply to kai klaas69:

    Hi Kai,

    Update schematic final. I draw schematic from a circuit board of micro x-ray manufacturer Kevex.

     

  • In reply to Lai Hai:

    Lai,

    I believe you are building the schematic based on the circuit board layout. This can easily lead to errors.
    Can you measure the voltage at the test point and the voltage at pins 4 and 8 of LM358?

    Regards,
    Ronald Michallick
    Linear Applications

    TI assumes no liability for applications assistance or customer product design. Customer is fully responsible for all design decisions and engineering with regard to its products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning Customer's design. If Customer desires engineering services, the Customer should rely on its retained employees and consultants and/or procure engineering services from a licensed professional engineer (LPE).

     

  • In reply to Ron Michallick:

    Hi Ron Michallick,

    I checked pin 4 connected GND and pin 8 connected Vcc 

  • In reply to Ron Michallick:

    Ron Michallick,
    I think test point is input signal.
  • In reply to Lai Hai:

    Hi Lai,

    I don't think so. The input signal should be applied to the upper end of R14, where you have made a connection to GND. The pot R15 in combination with R13 and R14 could form an adjustable voltage divider.

    Ron asked you to measure the potentials at pin 4, pin 8 and the test point. Have you done this? Could you please give us the results?

    Kai
  • In reply to kai klaas69:

    Hi Kai,

    PIN 4 = 0V, PIN 8= 5V

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