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Type: Posts; User: wwfeldman

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  1. Closed: Re: Scoping the post rectifier DC bus in a 240VAC , 100W PFC'd flyback

    i thought worst conditions were max line and minimum load, and minimum line and maximum load?
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    Closed: Re: Incident wave definition

    maybe you should explain a little more about what you want to do
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    Closed: Re: Incident wave definition

    incident wave is an incoming wave

    if one is far enough from any wave source (water, sound, EM), the incoming waves look like plane waves
  4. Closed: Re: Scoping the post rectifier DC bus in a 240VAC , 100W PFC'd flyback

    is there anything different in the variuos scope traces other than the voltage scale and the x10 scope probe and diff probe?

    you said its a 100W converter. what is the actual design level and...
  5. Closed: Re: Scoping the post rectifier DC bus in a 240VAC , 100W PFC'd flyback

    input frequency is 50Hz as seen by the 10 ms for 1/2 cycle

    what is the frequency of the PFC stage? i think you're seeing the switching
    stretch out the time scale and see if the "noise" looks...
  6. Closed: Re: Does the Razavi cover art make any sense?

    you're probably right about the two inputs of the op amp
    note however that all other connections have a dot on them

    as for the topology, its just cover art

    i think you'll be better off looking...
  7. Closed: Re: Resistor mismatch hand calculation and simulation

    There are several different ways to propagate error (uncertainty)
    This is one:

    For f(x,y,z), the uncertainty in f(x,y,z) is given by: ∆f(x,y,z)=f√((∂f/∂x)^2+(∂f/∂y)^2+(∂f/∂z)^2 )

    that is, the...
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    Closed: Re: Is it a transistor or a mosfet?

    see this thread

    https://www.edaboard.com/showthread.php?385762-IFC-TG179-TO-92-(transistor)&goto=newpost

    i200yrs started it on July 14 2019
  9. [SOLVED]Closed: Re: Generating Sine Wave Through External DAC (STM32)

    you might calculate the values you want to send to the DAC external to the processor
    and program in 360 data points

    or as Susan has described, 90 points and be clever

    or, since powers of 2 are...
  10. [SOLVED]Closed: Re: Generating Sine Wave Through External DAC (STM32)

    s[m] = 127+round( ( sin( I * 6.28/360) ) /0.02 )
    1 2 3 3 2 1

    by counting parenthesis, you can see that...
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    Closed: Re: Where does this equation come from?

    see the Wiki article:

    https://en.wikipedia.org/wiki/CORDIC

    there are several references at the end
  12. Closed: Re: Resistor mismatch hand calculation and simulation

    standard deviation is not tolerance

    two resistors in series add
    the appropriate way to add the tolerance, or standard deviation is square root of sum of squares of (tolerance or standard dev) in...
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    Closed: Re: PIC Controller Hanging

    is the motor controller malfunctioning or is the display controller malfunctioning?

    what is different between the sometimes it works and sometimes it doesn't work?

    what is the criteria for...
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    Closed: Re: How can I parameterize the curve

    try a sphere - use the bottom half

    http://mathcentral.uregina.ca/QQ/database/QQ.09.03/jaidev1.html

    and put a cylinder on top

    what kind of coordinate system does the software use? ...
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    [SOLVED]Closed: Re: Protect FPGA Pin from negative voltage

    that's all it takes. you're an electronics engineer. go study


    no such thing as a stupid question
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    Closed: Re: How can I parameterize the curve

    do you need help writing equations for the shape,
    or do have equations and need help implementing if in HFSS?
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    Closed: Re: Different Capacitors Recognition

    i don't think you can tell, in general, what is inside the case by just looking at the outside

    you need to read the part numbers and look up the data sheet.

    a 14 pin DIP is a 14 pin DIP until...
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    Closed: Re: buzzer and timer construction

    i think its rooster not roaster
    you know, a male chicken announcing sunrise on the farm?

    no idea about the dutch pot cover
  19. Closed: Re: Data Transfer over long rwisted pair cable

    you might consider this, from the CRC Handbook of Modern Telecommunications
    ...
  20. Closed: Re: Loosing data in verilog in case of calculation of variance?

    i see the reading in of 5 data points
    i see the calculation of the average (data_mean)
    i see the calculation of the sum of squares divided by number of data points (data_diff_sq)
    i see the...
  21. Closed: Re: Problem with PIC16F877A, infinite loop output voltage 0.6V

    are you reading port C or port D?

    can you use an interrupt instead of a loop?
    any key press causes an interrupt and the interrupt routine evaluates which key was pressed
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    Closed: Re: LM2577 external mosfet

    I do not think you can add an external switch to the LM2577

    Page 14 Figure 32 shows the operation of the LM2577.
    The current sense resistor, that provides a feedback into the control loop, is...
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    Closed: Re: Just want to say Hi!

    not everyone is a native English speaker
    even those that are, (UK and USA) spell things differently

    to paraphrase Duke Leto in Frank Herbert's DUNE,
    one has to make allowances for differences in...
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    [SOLVED]Closed: Re: Why is CO2 a green house gas?

    EM radiation from the sun is approximately a black body (cavity radiator) at about 5500 kelvin
    EM radiation from the earth is approximately a black body (cavity radiator) at about 300 kelvin
    ...
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    Closed: Re: Could this electric shower be lethal?

    I think it depends on what is inside the shower head and how its wired.

    The two lines from the power plug must go to a heating element. If the ground wire is not connected
    then all of the...
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