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  1. BobK

    Variable Current and Voltage Regulator - LM317T

    Please read my posts #8 and #10. You are not connecting it correctly. The LED should be connected to the center pin (Vout). And the battery plus terminal should be connected to pin 1 (Vin) in your diagram. If you insist on wiring it incorrectly, I cannot help you. Bob
  2. BobK

    Variable Current and Voltage Regulator - LM317T

    You have the LED connected to the adjust terminal in the photo you posted. Did you correct that? What do you mean by "input the current from Vout" The Vout pin is the pin that ought to be connected to the LED. Is this what you mean? If so that is what is supposed to happen, so what is...
  3. BobK

    HELP with normally open circuit

    Most relays have normally open and normally closed contacts. You would use the normally closed ones. Bob
  4. BobK

    Converting a security camera to be wireless

    Are you willing to spend about a year on this? That is what I expect it would take if you are a good learner. Bob
  5. BobK

    Variable Current and Voltage Regulator - LM317T

    It is wired wrong. The output to the LED should come from the middle lead of the LM317. However, I stronly reccommend that you use the constant current mode instead. That is the proper way to drive high power LEDs. You will also need heat sinking on the LM317, by the way. Do not wire it up...
  6. BobK

    Variable Current and Voltage Regulator - LM317T

    LEDs are rated for current. The voltage varies from one to the next even of the same type. The LED will not be destroyed as long as you don't exceed the max current. However, for a 5 Watt LED, you WILL need heat sinking or you will destroy it by overheating. Bob
  7. BobK

    Variable Current and Voltage Regulator - LM317T

    http://users.telenet.be/davshomepage/current-source.htm A 1.8R resistor would give you about 700ma. Bob
  8. BobK

    Variable Current and Voltage Regulator - LM317T

    Nothing, except that it is not a current regulator, it is a voltage regulator. You do understand, also, that you cannot control current and voltage independently? If you want a constant current, the voltage will vary with the load, if you want a constant voltage, the current will vary with...
  9. BobK

    Help Making an RF controlled relay!

    Making the circuit from scratch would cost you a lot more than buying it. Check out Ebay, for example: http://www.ebay.com/itm/AC-433M-RF-Remote-Control-Controller-1-Relay-1-Channel-/140579532017?pt=Home_Automation_Controls_Touchscreens&hash=item20bb316cf1 Bob
  10. BobK

    Factors that increase/decrease C-EMF

    Back EMF is dependent on the load. The larger the load the larger the back EMF. If you are thinking about how to reduce it to get better efficiency forget it. It is basic physics: conservation of energy. If there were no back EMF when you spun a generator, you could spin it with no effort...
  11. BobK

    Touch switch help!

    Did you try lowering the resistor, to say 1K? Bob
  12. BobK

    Capacitors & Resistors in Amplifiers

    They make it a filter. The one on the input of your circuit is odd. I would expect the capacitor and resistor to be in series, not parallel. The one in the feedback loop is a low-pass filter. As the impedance of the capacitor gets low (at high frequencies) it limits the gain to 1. Bob
  13. BobK

    infrared linear actuator

    You can get 3 pin IR recievers that would replace everything up to the transistor and relay at the output of the circuit you have linked. Here is a tutorial on them: http://learn.adafruit.com/ir-sensor Bob
  14. BobK

    Why the pull-up resistor is used with debounce buttons?

    You cannot simply connect a button to a digital input, because, when the button is not pressed there would be no signal on the input. This is called a floating input. In CMOS logic, a floating input can give undefined results, it may read as either high or low. the pull-up resistor guarantees...
  15. BobK

    Can one coil be a generator?

    Yes, a flywheel would recapture some of that energy. Bob
  16. BobK

    how to detect laser reflection with photodiodes

    The detection should be possible, but I wonder how you would determine the direction to the target? Bob
  17. BobK

    Can one coil be a generator?

    Because to push something back and forth, continual acceleration is needed, whereas to rotate something it is not, once it is up to speed. Unless you can completely recover the extra energy needed to accelerate the piston, you have lost energy that you would not lose in a rotating system. Bob
  18. BobK

    how to charge and then using the capacitor?

    For continuous operation, you gain nothing, and add weight. Bob
  19. BobK

    Can one coil be a generator?

    Except that it is it probably much less efficient than spinning the magnet or coils. Bob
  20. BobK

    Pcb etching problem

    Not to mention you can get finer lines that way. I have used one of these to fix up my laser printed boards if it missed something when I ironed it on: http://www.staples.com/Sharpie-Ultra-Fine-Point-Permanent-Markers-Black-Each/product_498386 bob
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