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  1. Replies
    38
    Views
    1,605

    Closed: Re: 12 Bit ADC with interfacing SPI in STM32

    Hi,

    Maybe it's time to start from the beginning ...
    An engineer should start with specifying the requirements (forget about all the ADC and SPI stuff)

    You show several different input...
  2. Closed: Re: ds1307 Rtc clock running slow by 6 second per day.

    Hi,

    Maybe a production problem
    .. some 32768 Hz XTALs donīt like ultrasonic cleaning.

    Klaus
  3. Closed: Re: Getting trigger signal for 555 timer from elevator button.

    Hi,

    there are millions. For a million of different requirements.

    But the most important - IMHO - is a proper PCB layout.
    The next important is an analysis of what really causes the error.
    ...
  4. Closed: Re: Getting trigger signal for 555 timer from elevator button.

    Hi,

    then itīs most probably an EMC problem, not a problem of the schematic.

    Use: (urgent)
    * PCB with solid GND plane
    * proper decoupling capacitors on ech supply pin of each IC
    * EMC filters...
  5. Replies
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    Closed: Re: Isolated Converter RS-422

    Hi,

    I donīt understand.
    Isolated but with no switching regulator.

    Due to the RS-422 you need energy to drive the 50 Ohms impedance signal lines. Where does this energy come from? Battery?...
  6. Closed: Re: Getting trigger signal for 555 timer from elevator button.

    Hi,

    There are many solutins.
    I'd go this way:
    * use a 10k pullup on TRIG pin to 12V
    * use a diode from TRIG (A) to the pushbutton (C)

    Klaus
  7. Closed: Re: ds1307 Rtc clock running slow by 6 second per day.

    Hi,

    Datasheet says:
    Did you read and follow the application note?

    Klaus
  8. Replies
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    544

    [SOLVED]Closed: Re: Wiring of DC fans in Series

    Hi,

    I agree.

    But the OP asks about series connection.

    Klaus
  9. Replies
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    1,605

    Closed: Re: 12 Bit ADC with interfacing SPI in STM32

    Hi,

    Please read all my posts...especially those with "sampling rate" and what is meant with "toggle NSS".
    It's all written already.

    Klaus
  10. Replies
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    256

    Closed: Re: L293d - Input Voltage (motor operation)

    Hi,


    General rule:
    Don't leave any inputs floating, neither at digital ICs nor at analog ICs...as long as it is not mentioned otherwise in the datasheet.

    Floating means the voltage level is...
  11. Replies
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    [SOLVED]Closed: Re: Wiring of DC fans in Series

    Hi,


    The two resistors are no "15V" generators. They just divide the input voltage by 2.

    --> If your supply voltage is 10V then the voltage at the divider will be 5V.
    Depending on unsymmetry...
  12. Closed: Re: Battery cutoff voltage vs 0% battery voltage

    Hi,


    What advice do you expect?

    Cutoff voltage depends on battery, not on application.
    For sure you may measure the battery voltage...but it gives not much information about health and charge...
  13. Replies
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    544

    [SOLVED]Closed: Re: Wiring of DC fans in Series

    Hi

    Try this:
    * NPN, PNP, 2x R = 4k7

    Wire it this way:
    * 30V --> NPN_C
    * NPN_E to PNP_E = 15V output
    * PNP_C to GND
    * resistors in series, one end to 30V, the other end to GND.
  14. Closed: Re: Holding button for 2s to trigger 555 timer

    Hi,

    On button press: the capacitor gets slowly discharged by a high ohmic resistor
    On button released: the capacitor fastly gets discharged via a diode

    Klaus
  15. Replies
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    1,605

    Closed: Re: 12 Bit ADC with interfacing SPI in STM32

    Hi,

    read my previous posts

    that's the wrong way round

    Klaus
  16. Replies
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    119

    Closed: Re: At45db041b vs at45d041

    Hi,

    If I need to know that, I'd compare the datasheets.

    I'd focus on voltage levels, timing...

    Klaus
  17. Replies
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    256

    Closed: Re: L293d - Input Voltage (motor operation)

    Hi,


    You should not guess, better read the datasheet.
    It clearly says every input voltage above 2.3V is valid HIGH level.

    Better than long textual description is a picture.
    --> please show...
  18. Replies
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    [SOLVED]Closed: Re: Wiring of DC fans in Series

    Hi,

    A power voltage divider could be made with two equal resistors, an NPN and a PNP...
    Not very precise, but good enough for fans

    Klaus
  19. Replies
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    1,605

    Closed: Re: 12 Bit ADC with interfacing SPI in STM32

    Hi,

    Your scope picture (especially the upper one of post#29) is awful. Don't you recognize that the sampling rate is much too low for your signals. The SCK looks far away from being a square wave....
  20. Closed: Re: Generation of 4 Phase Shifted clock Signals

    Hi,

    From your first post I thought about sinusoidal waveform with positive and negative voltage swing.

    Now it seems to be a squarewave...
    with unknown voltage swing.
    Unknown risetime and...
  21. Replies
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    503

    [SOLVED]Closed: Re: USB to RS232 exactly similar to COM1

    Hi,

    draw a sketch.

    Klaus
  22. Closed: Re: Battery cutoff voltage vs 0% battery voltage

    Hi,

    it (solely) depends on the battery.
    Read the battery datasheet or contact the manufacturer.

    Also visit www.batteryuniversity.com

    Klaus
  23. Replies
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    Closed: Re: Using AD831 in parallel

    Hi,


    I doubt the PCB is getting hot. Usually the electronic parts getting hot. .. and only some of them.

    To detect which one is getting hot:
    * power off and let all get down to room...
  24. Replies
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    [SOLVED]Closed: Re: USB to RS232 exactly similar to COM1

    Hi,


    No.
    It just says it works with your computer, but it does not say anything about compliance.
    *****
    True: RS232 idle state = high = 1 = negative voltage (lower than -5V)
    *****
    ...It...
  25. Replies
    5
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    224

    Closed: Re: Using AD831 in parallel

    Hi,

    First you need to determine:
    * How much current can your supply deliver
    * How much current do you expect your circuit to draw
    * Measure how much your circuit really draws

    We don't know...
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