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  1. BobK

    How can I become circuit designer

    Not unless you are doing mechanical design. Bob
  2. BobK

    HUGE NOOB, need help please!

    Well, there is a big difference between 3.6V at 20mA and 3.6V at 10A. Is this a small indicator LED or is it a power LED designed for lighting? If the circuit is correct and the LED is lighting as expected, then it is probably too powerful to be run off AA batteries, though is it hard to...
  3. BobK

    HUGE NOOB, need help please!

    What is the max current rating of the LED? Bob
  4. BobK

    need advice/help on dual laptop psu mod (load balancing)

    Everyone seems to be missing what the OP is doing. Steve, did you see this part? Bob
  5. BobK

    need advice/help on dual laptop psu mod (load balancing)

    No need to butt out. I agree that the OP is not very clear on what is happening. Bob
  6. BobK

    beer robot motor selection

    I agree with sndscientist. Look up spud cannon. Bob
  7. BobK

    How can I become circuit designer

    You've told us about what equipment you have bought. That is completely irrelevant. What kind of circuits have you built? What would you like to build? What kind of problems have you had? What books have you read? These are the more pertinent information we would need to assess what you...
  8. BobK

    need advice/help on dual laptop psu mod (load balancing)

    Kris, Then one of use is misunderstanding this statement. Bob
  9. BobK

    pn junction reverse bias working

    For the same reason they cannot in a capacitor. In fact, a reversed biased diode acts like a capacitor. A small current will flow until it is charged. Bob
  10. BobK

    Fun with solenoids

    Yes, that would be better. bob
  11. BobK

    Fun with solenoids

    Look at how a car window actuator works. Bob
  12. BobK

    Need guidance; newbie project - LED controllable steps

    An advantage of the uController though is that once you have the hardware hooked up, you can play with the software to get addditonal effects. For instance it might be cool to have the leds on all the stairs strobe in a chaser pattern in the direction the person is walking. With a uC, this is...
  13. BobK

    HUGE NOOB, need help please!

    And the formula will give a 0 Ohm resistor since 3.0 - 3.0 = 0. Is the LED lighting? I suspect you are simply shorting the battery. An LED with a forward voltage of 3.0 to 3.6 should not draw too much current from a 3.0V battery. Bob
  14. BobK

    Rotary motor specs & step-changing voltage

    Just out of curiosity, why do want to do this? I have never heard of applying a randomly varying voltage to a motor. Bob
  15. BobK

    need advice/help on dual laptop psu mod (load balancing)

    What is shutting down? Is it the power supply or the laptop itself? It is it the laptop, supplying more power is not likely to fix it. Bob
  16. BobK

    What does C rating mean for batteries? Speed of discharge?

    Fire can be deadly at any voltage. Bob
  17. BobK

    PIC Hex Files

    Are you sure the "false address" is not actually the address of the EEPROM? In a PIC program, you can read and write both program memory and EEPROM with the same instructions, at different addresses. For example, addresses from 0 to 00ffff is program memory and 10000 to 100ff is EEPROM. I...
  18. BobK

    Woo-Woo OVERUNITY??? you do the math

    Kris, did you try clicking the links? It is a joke. Bob
  19. BobK

    What to do with 0.5 V and 25 mA?

    Pretty much any general purpose NPN will do. I used a 2n3904. Did you try reversing one of the transformer windings connections? They have to phased correctly in order for it to work. Also, did you try using a 1.5V battery? It might not work at 0.5V. 25ma should be plenty to operate it. Bob
  20. BobK

    What to do with 0.5 V and 25 mA?

    I built a Joule Thief from parts in my cabinet, so, not hard to find at all. The only questionable one is the ferrite torroid, which I reclaimed from a random inductor I had taken out of something. Bob
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