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  1. KJ6EAD

    Knight Light

    The 6-LED 4017 circuit has 8 of it's outputs ORed together with diodes to create the bidirectional effect. The sequence is: 0, 1+9, 2+8, 3+7, 4+6, 5. The + symbol is a logical OR. Using this same strategy with two cascaded 4017s would yield N / 2 + 1 = 20 / 2 + 1 = 11 LEDs, then the sequence...
  2. KJ6EAD

    New to soldering, please read within

    Are you trying to start a war? There are several products from several manufacturers that are well regarded but the answer, if there is one, would depend on other process factors such as lead, land and pad materials and finishes. Can you define "best"?
  3. KJ6EAD

    Re: 5 mm square LED. Solution needed.

    Most perf/strip/pad-per-hole/vero boards have holes sized around 0.040" so the component leads won't fit through them.
  4. KJ6EAD

    Re: 5 mm square LED. Solution needed.

    Most of the methods suggested would require bending the leads a bit in two axes. The leads are also too wide for most prototyping PCBs. If you're willing to bend them a little more, you could solder them onto a component carrier. Your problem component: A DIP component carrier:
  5. KJ6EAD

    The newbie's secret circuits circus

    That's why you hire the one's with the high GPAs. The cheaters fail the tests and get barely passing grades. Simple interview questions will also sink the posers. Do you have macros programmed for "Google is your friend." and "Read the datasheet."?
  6. KJ6EAD

    The newbie's secret circuits circus

    In my opinion, useless titles like "HELP" should be considered a rule violation and subject to moderator action including, but not limited to, arbitrary retitling. On another forum, for a long-running thread, I located an important unit-specific document, helpfully posted it and made...
  7. KJ6EAD

    Young jedi needs pcb/switch type assistance!

    Could you solve the space problem by separating the AAA battery holder and inverter using a new battery holder? I don't have much confidence in a 9V battery holding up well, especially while dropping ~6V through a regulator. It looks like your housing has a partition of sorts. Would it be...
  8. KJ6EAD

    Level 2 newby with a few questions

    One more even more minor item. The V for voltage should be capitalized.
  9. KJ6EAD

    Sound activated LEDs

    Maybe you should think about using a Velleman MK186 and some prewired LED strips. The strips can be cut in 3" segments and if you need more LEDs per inch, you just stagger more strips side by side. The strips come in a couple of different LED spacings and some are double width. Just add a power...
  10. KJ6EAD

    What is this box looking thing??

    My guess is a power supply. I think I see large diodes in parallel, front panel binding posts and possibly some large capacitors with ceramic terminal insulators. Or it could be a cold war era mil spec coffee urn heater. :p
  11. KJ6EAD

    generating heat from AA battery

    You're not going to explode a cell discharging a AA alkaline battery at a 500mA rate. If we refer back to the example I gave earlier of a 5Ω resistor and a battery with a 1Ω internal resistance, the resistor produces 83% of the heat and the battery produces the remaining 17%. When you reduce...
  12. KJ6EAD

    generating heat from AA battery

    Both. Batteries have internal resistance. When you connect a resistor to both terminals of a battery you create a series circuit composed of two resistances and a voltage source. Since a series circuit has the same current flowing through all components, the heating in components is proportional...
  13. KJ6EAD

    generating heat from AA battery

    You'd be lucky to get 0.5W for 3 hrs. You might try a 4.7Ω or 3.3Ω, 1W resistor. http://www.powerstream.com/AA-tests.htm
  14. KJ6EAD

    Questions from someone just getting into electronics, and DIY

    Check the link in my edited post above. The handwritten on graph paper look is used in all of the Mini Notebooks as well. It's his trademark style. Those color changing LEDs usually just want about 4 Volts and their current will vary up to =65mA.
  15. KJ6EAD

    Questions from someone just getting into electronics, and DIY

    Mr. Mims has written a library full of project books so you might like some of them. http://www.forrestmims.com/engineers_mini_notebook.html
  16. KJ6EAD

    Build part list from schematic

    Since it's not so much the creation of a bill of materials as component identification and specification you'll have to ask about individual parts that you don't know.
  17. KJ6EAD

    Questions from someone just getting into electronics, and DIY

    It seems like we just answered a very similar set of questions recently. Take a look at this thread: https://www.electronicspoint.com/start-t249895.html. The book by Forrest Mims should be about right, somewhere between Make: Electronics and The Art of Electronics. You can get unspecified...
  18. KJ6EAD

    Level 2 newby with a few questions

    See my edited post above for more explanation and a speculation.
  19. KJ6EAD

    Level 2 newby with a few questions

    It's all Ohm's law applied. I took your maximum current and voltage and multiplied them together to get a wattage figure for the motor (0.27A X 3V = 0.81W). Because a resistance in series with the motor will divide voltage and have equal current this wattage is the maximum that the resistive...
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