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  1. BobK

    Battery doesn't power microcontroller as expected

    Just looked at the user guide. It calls for a 47K pullup and 2.2nF to ground on the ~RST pin. Try that. Bob
  2. BobK

    Battery doesn't power microcontroller as expected

    I looked at the datasheet and answered my own question. Yes it does have a reset pin. Try a 10K pullup on the ~RST pin. But... You probably killed the chip when you put 9V, or even 6V on it since the absolute max is 4.1V. Does it still work in the launch pad board? Bob
  3. BobK

    Battery doesn't power microcontroller as expected

    Is there a reset pin? Are you driving it with something? Bob
  4. BobK

    555 output to transformer failure

    Is it out of the question to use a standard 9V? That would take maybe twice the space of 3 CR2032s. BYW, I tried to design a boost converter. With the 40 Ω internal resistance and could no achieve your voltage requirements without using a large inductor (1mH or so) which would be larger than...
  5. BobK

    555 output to transformer failure

    I assumed he meant 1 stack of 3 in series, but who knows? Bob
  6. BobK

    Transistors for higher voltages

    Somehow I missed the "two" in the OP. It was the 80V source to drain and the 40V rating that I saw. If you wire two in series taking precautions to make sure neither has over 40V across it, that is a different story. Bob
  7. BobK

    240V ac LED bulb failure

    Your paying $10 for LED bulbs? They are down to about $2 here. Bob
  8. BobK

    Transistors for higher voltages

    It does not matter which way you wire it, you will get the same result either way: a blown transistor. Bob
  9. BobK

    555 output to transformer failure

    Then I think your project is doomed. Actually it is not, doomed, I think you could just make it by using a different inductor. Here is my reasoning. First, let's look at the current situation. Inductor is 3.3uH. At 90KHz, its inductive reactance is 1.9Ω. So you are driving it with a...
  10. BobK

    555 output to transformer failure

    What battery are you using that has an internal resistance of 40Ω? The typical resistance of a rectangular 9V alkaline is 1 to 2Ω. Bob
  11. BobK

    555 output to transformer failure

    In your OP, you state that the 40Ω resistor is internal resistance. Internal resistance of what? The battery? The inductor? In either case it is too high. Also, it is not clear if your results are coming from a real circuit or from simulation, which is it? I simulated a simplified version...
  12. BobK

    What type of switch is this and how does it work?

    I suspect it is switching no inductance (for high speed) and two different inductances for lower speeds in series with the motor. These days, capacitors are usually used for this purpose, but inductors should work just as well. Can you trace the wiring and draw a diagram, include the power in...
  13. BobK

    555 output to transformer failure

    Can you link to a datasheet of the inductor? Bob
  14. BobK

    555 output to transformer failure

    A transformer with that kind low an inductance is for use in the Megahertz region. Bob
  15. BobK

    TEC modules (body heat) powered charger

    Have you calculated how much power is available from body heat, taking into account the efficiency of the TEGs and determined how long it would take to charge your phone? Bob
  16. BobK

    555 output to transformer failure

    3.3uH is way too small. Bob
  17. BobK

    Measure very low valued photoresistor

    I believe that circuit is for a photodiode, not a photoresistor. Bob
  18. BobK

    Transistor LED circuit_LED not blinking

    I would not expect that circuit to oscillate. Where did you get it? Bob
  19. BobK

    Attaching multiwatt chip

    Or mount the IC on a heat sink and use wires to connect it to the stripboard. Bob
  20. BobK

    Supercapacitor Track Car Starter

    Where you go wrong is how fast it can deliver that charge. An AA battery can deliver about 1A. A capacitor, depending on it's structure, can deliver 100s of A. The total energy of the battery may be higher, but it cannot all be released in the second or two that it takes to start a car. Bob
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