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  1. KrisBlueNZ

    Woo-Woo Why are there countless attempts to make magnets power generators..

    Nice explanation, timothy48342!
  2. KrisBlueNZ

    Woo-Woo Why are there countless attempts to make magnets power generators..

    I'm afraid I can't view that video at the moment, I'm limited to dial-up speed because I've used up my monthly data allocation :-/ Regarding magnetic attraction or repulsion as a kind of ENERGY... think of a compression or tension spring. When you squeeze a compression spring, you feel a force...
  3. KrisBlueNZ

    Woo-Woo Why are there countless attempts to make magnets power generators..

    I think the trick is that magnetic attraction and repulsion seem, at first glance, to contain some kind of energy source, and it seems like it should be possible to extract that energy. But as you say, a bit of education soon makes it clear that this is an illusion. Everyone who doesn't...
  4. KrisBlueNZ

    go kart lap timer

    That's an interesting problem. As you've already found out, a static magnetic field and a hall effect sensor won't work, because they need to be much too close for that application, where the go kart is bouncing around and needs reasonable ground clearance. The magnetic loop idea, I assume...
  5. KrisBlueNZ

    Woo-Woo Why are there countless attempts to make magnets power generators..

    I think perhaps the fact that magnets seem to be "magical", or at least inexplicable, encourages people to think (a) that magnets can do things that seem to be impossible, and/or (b) that gullible folks are more likely to believe their claims of perpetual motion, >100% efficiency, and so on, if...
  6. KrisBlueNZ

    Newbie: What is this part?

    FYI this is a 3-pin ceramic resonator and it contains two built-in capacitors. The middle pin is the common of these capacitors, and will be connected to the ground rail in the remote. You need to replace it with a 3-pin ceramic resonator with built-in capacitors. (You can also get 2-pin ceramic...
  7. KrisBlueNZ

    how to write c code for motor

    On the AVR, PORTA is an output register. If you want to READ the port, use PINA.
  8. KrisBlueNZ

    MAKE: Electronics Ex. 10 Help Needed

    Right, if you look inside the LED (with a bright light if necessary), you may be able to make out a cup-shaped section with the actual LED chip sitting inside it, and a second electrode beside the cup with a fine wire going to the LED chip. "Cup is Cathode" is how I remember the rule...
  9. KrisBlueNZ

    Can somebody explain this simple circuit please?

    Yes, the capacitors will be charged slightly in the reverse direction, but only by about 0.5V. This doesn't cause a problem with a normal electrolytic that's rated at say 16V. In that astable multivibrator circuit, when a transistor turns ON, its collector voltage falls rapidly to about 0.2V...
  10. KrisBlueNZ

    I have issues with MAKE: Electronics experiment 8? (The link may not work so tell me

    OMFG Steve and Laplace you guys are paragons of patience! It's like you're teaching someone to play a Beethoven concerto with Morse code as the only communication medium!
  11. KrisBlueNZ

    Latching circuit problem

    Dave Jones, who I've just recently discovered through electronicspoint, coincidentally, has a circuit that is probably exactly what the original poster wants. It's described in a rather drawn-out video at It is designed for a single Li-Ion cell but will work fine at 6V. You will have to use...
  12. KrisBlueNZ

    Need some creativity help...only 1 pin left

    So you have a device that provides an idle-high data signal to the PIC and you want to be able to force the PIC's input low in some circumstances? You could insert a series resistor and put an NPN to pull the PIC pin firmly low. Of course if you have an AND gate available it's even easier. Why...
  13. KrisBlueNZ

    Latching circuit problem

    Excellent advice throughout this thread, *steve*! I can see why you are a "super moderator" :-)
  14. KrisBlueNZ

    DC power supply

    If you're keen you could design a power supply with a switching pre-regulator and a linear post-regulator to get the best combination of efficiency with load transient response. This has been done before BTW. When your output is, say, 12V, have the switching regulator drop the unreg rail (40~60V...
  15. KrisBlueNZ

    Check battery charging progress

    Is it rechageable or not? A "dry battery" or "dry cell" is normally not rechargeable. In either case, it is difficult to estimate the energy remaining in a battery. To do a reasonable job you really need a smart device that can monitor current into the battery (for a rechargeable battery)...
  16. KrisBlueNZ

    Simple Question Regarding Isolating Car Batteries With Diodes

    You can also use MOSFETs instead of diodes to do the diode-OR function. This is more complicated but much more efficient, and therefore more compact because much less heat is dissipated, due to the lower voltage loss. The following page has an example schematic...
  17. KrisBlueNZ

    PC as Signal Generator

    It's too late now, but... Problem could be lack of DC path to ground. Sometimes the presence of headphones is detected when the L and R output signals at the jack are pulled to (or near) ground by the DC resistance of the headphones plugged into the socket (a weak pullup applies DC to the...
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