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  1. J

    DC generator problem...HELP!

    Any good PMA will produce three phase as it is more efficient. I didn't know small dc brushless motors had multi-phases, but it makes sense, seeing as how they would be smoother in operation and provide more torque.
  2. J

    What is a shield?

    The arduino is a micro-controller, shields are components that you add to an arduino that give it added functionality. The two are completely unrelated. http://www.adafruit.com/category/17
  3. J

    conductivity check need help

    If I understand you correctly then you will need to be able to measure the temp in hundredths of a degree to maintain a tenth of a degree accuracy. You need to know when to turn the heating element on before it cools 1/10 of a degree. Vice versa, when it is heating. If you don't need that good...
  4. J

    DC generator problem...HELP!

    That thing looks tiny, exactly what are you using to turn this thing over?
  5. J

    starting motor with bridge circuit

    here we go again. The first thing on my mind is this sounds like homework. So what are the details of the assignment? Have you even found a bridge circuit that you want to write a report about? Google will help you with that if you don't already have one.
  6. J

    conductivity check need help

    .1 degree accuracy? I can't solve your sensor problem, but just a thought when I was reading this. If you have something that had a high thermal mass to either contain your flask or sit underneath your flask it would seem a lot easier to maintain a temp for 20 seconds I would think. I would...
  7. J

    Use Electromagnetic energy to crush a aluminium can?

    http://members.tripod.com/extreme_skier/cancrusher/ Parts wise very similar. Seems to me though you need high voltage if this guy is correct. Notice that the use of his spark gap means he has to be no where near the apparatus when it is charging or going off. Edit: it is quite clear after...
  8. J

    Something better than a potential divider

    I looked up a op-amp and it can have up to a voltage difference of 30V on the inputs, which would work for you since you don't want your batteries to ever go below 24V less then 65V. Then you could use the buck converter to power your comparator. Keeping it within the rated limits. If you used...
  9. J

    Something better than a potential divider

    Why would you just not use a dc-dc converter to get your different voltages? They would be more efficient then using a resistive component like the VR. I am also not sure why you would make your reference voltage at 41V instead of ground potential. You risk shock and failure of your components...
  10. J

    What do you call these female pins on digikey?

    After hours of searching I finally found what I was looking for and in the process taught myself something about electronic suppliers and parts. When all else fails ask technical support. These are the housings of the connectors in the picture that steve posted. On down the webpage you will...
  11. J

    What do you call these female pins on digikey?

    I am not poor, I would rather pay extra or do extra work then to wait 3 weeks for something as simple as a wire. It even says in the ebay ad not to buy if I can't wait 3 weeks for delivery and I can't wait. I find it unbelievable that I can not buy the male and female connectors like this online...
  12. J

    LED vs Diodes

    You don't need a diode unless you want to stop the led from flickering when using AC. As the LED will flicker at 60Hz. The trick I have seen to stop them from flickering is to use a diode and a capacitor to run the led on the negative cycle. during the positive cycle the LED will work as usual...
  13. J

    What do you call these female pins on digikey?

    http://www.ebay.com/itm/Jumpers-Wires-Male-Female-QTY30-Compatible-Arduino-/250641028508?pt=LH_DefaultDomain_0&hash=item3a5b5e959c#ht_1738wt_1396 This is really what I need, but I refuse to buy from china!!! Delivery takes forever, especially around the holidays. I should be able to make these...
  14. J

    Hello all

    Hi, welcome to the forums. Do I dare ask what a willow burning sterling engine is? This isn't like one of those flame eater engines is it?
  15. J

    LED vs Diodes

    Do you happen to know the type of LED you are using. As bob has said, the reverse breakdown voltage of the diode must be able to handle the 13VAC negative cycle or it would have been destroyed by now. But, the datasheet should prove this as well.
  16. J

    What do you call these female pins on digikey?

    thanks harald. But, what do they call the female version that would fit over top of the male breakaway connectors? I see I can use the male breakaways, solder my wire to them and then use a piece of heat shrink tubing to keep it isolated for the arduino. Still little confused on the driver board...
  17. J

    What do you call these female pins on digikey?

    The 10 pin header pins on the left most part of the board J1 - J2. I need to connect some wires to these. What is it that I am looking for on digikey? I want to attach them to an arduino uno that has the female version of these pin headers. What would you suggest or use if you wanted to wire...
  18. J

    energy saving circuit

    Seriously though, can we get a sticky to help people help themselves? I mean I have seen too much of this recently. It makes like zero sense to have these threads on here. Let alone when they show up in my 100 results when I do a search. I need all the help I can get and this isn't helping.
  19. J

    DC/DC Power Supply Help

    What do you have against the design that you need to change it? Essentially your gonna be creating the exact same thing. Why do you wish to reinvent the wheel? Yes, but the LM317 is only designed for at it's max 1A, you will however get less then that. Also, VR's are very inefficient the...
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