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  1. BobK

    Bleeder resister size

    If the resistor is connected all the time, it would have to be at least 2W. If you only connect when it is powered off, I suppose you could get by with less. Bob
  2. BobK

    what exactly is Voltage

    Nope. For the second time, you are thinking only in terms of a capacitor, and even then, charge is just one of the parameters that determine the voltage. In a battery, the voltage is due to the difference in potential energy of two different chemical states. A voltage can also be created by a...
  3. BobK

    Bleeder resister size

    Sorry, Dave, but at 125V a 10K resistor will dissipate 1.6 Watts. A 1/2 W resistor ain't going to make it. Bob
  4. BobK

    Basic's

    I always amazes me what people think is a small and simple project. A small and simple beginner project is to light and LED from a battery. Next step to make it flash. Your project would be best done with a microcontroller, which is not a small and simple project for a beginner. It...
  5. BobK

    Question in Char Separating

    You apparently need to learn programming. I presume, from your use of "char" that you are using C. Find a C tutorial and study it. Bob
  6. BobK

    what exactly is Voltage

    Or, more illuminating, what we measure in Joules / Coulomb. I.e. the voltage between point A and point B is the energy needed to move 1 C of charge between the two points, which is what I said in post #4. Bob
  7. BobK

    Question in Char Separating

    The world will not fit in a byte. Bob
  8. BobK

    Intel enters the Arduino market

    In addition to the Arduino environment, the board can run Linux and be programmed with gcc, so I would say yes to your question about enhanced capabilities. The price is $60. Bob
  9. BobK

    LED Flasher help.

    Kris, Nice tutorial! If I had the time (maybe someday I will) I might do the same design with a PIC micro for comparison. The hardware gets a lot simpler, so the tools and the programming would be the thrust of my tutorial. Bob
  10. BobK

    New to the forums and looking for some advice

    The AVR microcontrollers already have protection diodes on the inputs and state the input voltage limits as Vdd-0.5 to Vcc+0.5 V. So any external diodes must conduct at less than 0.5V in order to do any good. I would use Schottky diodes for protection. Bob
  11. BobK

    Want to on and off solanoid valve using MOSFET

    I have to disagree. Figure 1 shows it passing 10A with a Vgs of 4.5V. http://www.irf.com/product-info/datasheets/data/irf540n.pdf Bob
  12. BobK

    low power transformer with high current output

    You can multiply the current only if you lower the voltage. Power = Voltage * Current. You cannot create more Power than the transformer is rated for. Bob
  13. BobK

    Intel enters the Arduino market

    TI also: http://www.theverge.com/2013/10/5/4805844/arduino-tre-from-texas-instruments-promises-100x-power It looks like Arduino is going high speed! Bob
  14. BobK

    Intel enters the Arduino market

    Interesting. an Intel Architecture Arduino compatible board. http://www.intel.com/content/www/us/en/do-it-yourself/galileo-maker-quark-board.html disclaimer: I am an Intel employee, but I thought this was of enough interest to the forum that it should not be interpreted as advertising...
  15. BobK

    Need help to build police siren/LED flasher

    1. Trim those leads! 2. The solder should have flowed to cover the entire pad if done correctly. Put some flux on them and reheat until each solder joint looks like a little cone, covering the pad and going up the lead. Bob
  16. BobK

    what exactly is Voltage

    No, charge is not always the source of voltage. In your example of a capacitor it is, but not always. Again, it is the amount of energy it takes to move a charge from point A to point B. Say there is a resistor with current flowing though it. The amount of work (energy) needed to get a unit...
  17. BobK

    what exactly is Voltage

    Voltage is a measurement of how much energy is required to move a charge from point A to point B. This number can be negative, in which case energy is produced by the movement of charge. In your capacitor example, the more charge you have on the two plates, the more energy will be required...
  18. BobK

    New to the forums and looking for some advice

    Actually, a rotary encoder is what you want. It can tell the direction and speed at which a shaft is turning. This would be far more robust than using a small motor as a generator. Bob
  19. BobK

    LM317T and how it works

    Well, it wouldn't be much of a regulator if the voltage changed would it? Yes, the output voltage stays constant, as long as the input voltage is high enough (about 2-3V above the output) Bob
  20. BobK

    Steve Jobs Memorial Challenge

    If you truly want to make a tribute to Steve Jobs, you should work on selling it, not building it. Bob
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