Type: Posts; User: wwfeldman

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  1. Replies

    [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
  2. Replies

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

    if the previous discussion has not helped, reduce the program to only the clock
    leave out the alarms and anything else that is not directly clock
    see how that works

    then slowly add back one...
  4. Closed: Re: ds1307 Rtc clock running slow by 6 second per day.

    according to the Ap Note 58, page 7, the clock can run slow if there is a capacitance mismatch
    or stray capacitance or a variety of other things.
    Have you followed the recommendations therein, as...
  5. Closed: Re: ds1307 Rtc clock running slow by 6 second per day.

    what are the part numbers and the accuracy/tolerance specification for your crystals?
    you've used several from different sources? are all of them off 6 seconds per day? compared to what?
  6. Closed: Re: ds1307 Rtc clock running slow by 6 second per day.

    6 seconds per day is 6 seconds out of 86400 seconds per day
    or 6.944 x 10-5 or 6.944 x 10^-3 % or 0.007 % or 69 x10^-6 or 69 ppm


    depending on your 32.768 kHz crystal, this is...
  7. Closed: Re: Which transformers can pass approvals testing rergarding isolation voltage testin

    as i read the ferroxcube data sheet, page 423 (acrobat reader page 424)
    the surface mount pad layout has 2 mm wide pads on 3.75 mm centers
    therefore the separation between pads is 1.75 mm

  8. Closed: Re: Which transformers can pass approvals testing rergarding isolation voltage testin

    no disrespect intended
    copied and pasted from the Furukawa Electric Company website you quoted:

    Certified as reinforced insulation; three layers can resist up to 3,000 ACV for one minute.
  9. Closed: Re: Which transformers can pass approvals testing rergarding isolation voltage testin

    i do not think the issue is the bobbin
    i think the issue is spacing

    the only 8mm spacing i see on the bobbin you called out on page 732 is between the left side and the right side of the top view...
  10. Replies

    Closed: Re: Learning psoc technology

    I started with Cypress CY8KIT-059
    its is inexpensive, the software is pretty good, it is similar to the part(s) andre describes
    the user group is useful
  11. Closed: Re: What is the future of Boolean algebra-based languages and methodologies?

    analog is not useless
    really understanding how digital works requires understanding analog, using digital does not

    quantum computing is still a long way off and it may never be in consumer or...
  12. Closed: Re: What are the layout methods to make source to drain capacitance zero?

    i know nothing about ASIC design, etc
    but i do know a little physics

    you have two pieces of metal, separated by some distance - that is a capacitor

    you can reduce the capacitance, but you...
  13. Replies

    Closed: Re: STM32 16bit wav player using Dac

    i look at this in a simple way
    you have a 16 bit wav in a 12 bit DAC
    what happens to the other 4 bits?

    if the data is 16 bit, using 12 bits loses something

    you use the DAC right aligned
  14. Closed: Re: Limit Current Maintain Voltage PSU output

    what you seem to want/need is an active resistor to be in parallel with your load
    changing the behavior of this (so-called) active resistor may get close to what you want

    use a series current...
  15. Replies

    Closed: Re: 60W offline flyback PCB suffers burning

    blowing the resistor open sounds like a joule stress issue, not a regular heating issue
    (my estimates indicate the resistor should be okay under average conditions)

    joule stress is a result of...
  16. Closed: Re: stm32f103c8t6 vs stm32f103cbt6 vs stm32f103c8t6 vs stm32f103re6

    go to the manufacturer's website and read the documentation

    there are 29 variants of stm32f103
  17. Closed: Re: Active Precision Current Limiting circuit needed

    How precise is precise?
    Is the cutoff the important parameter?
    Is the slope of the cutoff important?
    How sharp a cutoff do you need?

    Depending on how critical 100 mA is, don't use a pot,...
  18. Replies

    Closed: Re: Help with wires names

    I call them connectors
    some sort of single row connector male, partly shrouded and keyed

    I see what looks like KLDZ on one
    is there a manufacturer's name and/or part number on them?
    what did...
  19. Closed: Re: 300W SMPS with low input capacitance at the end of a 10km cable

    Interesting question

    The output is about 300 W
    add about 10% over-design, 330 W
    assuming 80% efficiency, the source, at input to the device, is about 413 W, or about 0.83 A at converter input
  20. Replies

    Closed: Re: Replacement for AD848JR

    digikey claims analog devices has some

    it appears analog devices agrees...
  21. Replies

    Closed: Re: Adaptive passes did not converge

    What software are you using?
    what are you analyzing?

    you need to provide information so someone familiar with your software,
    or your type of issue can respond

    the better the information you...
  22. Replies

    Closed: Re: Absolute convergence criteria?

    any circuit bigger than a battery and a light bulb has two or more equations that must be solved simultaneously.
    the n subscript is the nth equation
    that is, there is a statement like...
  23. Closed: Re: li-ion voltage reducer to 3volt - help needed

    is the zener really 3.3V?
    increase the input voltage slowly to about 5 or 6 V - does the zener regulate?

    if you take the zener out, what is the voltage at the junction between the two resistors?...
  24. Closed: Re: To which standards must we conform for our electronics/electrical product?

    you'll likely need UR (underwriters labs) approval in US
    and CE mark in europe

    no idea what happens in UK after Brexit

    since its cosmetic, there may also be requirements from food & drug or ???
  25. Closed: Re: Sense input current of boost converter use Keysight power supply

    I suggest you look at the manual.

    usually the sense terminals of a power supply are for remote sensing of the power supply output voltage

    using them makes the supply output voltage correct at...
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