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  1. BobK

    USA to uk convert

    When I lived in Germany, we had a 1500W transformer. It was about 1 foot by 6 inches by 6 inches (30 x 15 x 15 in cm.) and weighed about as much a bowling ball (16 lb or 7kg.) Bob
  2. BobK

    Help with ADC conversion registers in PIC or possible logic in code flaw

    I am not sure I trust the C compiler to handle (ADRESH << 8) correctly. It should be converted to int before the shift, but if it is not, you would always get 0 as the result. Try changing it to ((int)ADRESH << 8) Bob
  3. BobK

    Help with ADC conversion registers in PIC or possible logic in code flaw

    You don't have to explicitly switch banks when using C. That is what compilers are for :) Bob
  4. BobK

    USA to uk convert

    So you agree with me, that a diode would cause it to operate at twice the power it was designed for? Or are you talking about running it directly from 240V? The comment would apply to either. Bob
  5. BobK

    USA to uk convert

    Tell my why my logic is wrong. Using a diode: You get the full voltage and current half the time. But both of these are double when you put 240V into a resistor as opposed to 120V. So you get 4 times the power half the time, or 2 times the average power at 240V with a diode compared to 120V...
  6. BobK

    Battery charger

    The charger has to be more than just a power supply. Is there additional circuity? If the pack has a thermistor, it should be monitoring that to determine termination of the charge cycle. If this type of circuit is in place, the difference between 11.6V and 12V probably will not matter. Bob
  7. BobK

    Dodgy Chinese flip flop...or my circuit?

    Try adding a pull up resistor on the trigger input. 1K for testing. I doubt this is the problem, but who knows, if there is no pullup on the board, the input might be floating between button presses and subject even to noise from the relay activating. Bob
  8. BobK

    555 output to transformer failure

    Yes, it is a bit easier to achieve the results with 12V instead of 6. Also, I have to ask, did you model the series resistance on the inductors? 200Ω on the secondary seems signficant. Bob
  9. BobK

    ground issues with switching batteries

    One way to solve your problem would be to use opto-isolators and logic level MOSFETS that could have the gate driven by the 4V batteries themselves. That way, no common ground is required. Bob
  10. BobK

    ground issues with switching batteries

    No, they will not. Your circuit has 24V shorted to ground through a forward biased diode. Guaranteed to smoke the diode. What type of batteries are they? Some types can be charged in series quite effectively. Bob
  11. BobK

    LM317 2N3055 Variable Circuit Problems

    A cap between out and ground is to smooth the output if there are sudden transitions in the load. If it was wired correctly, and the cap is not shorted, it should not cause any problems. Most likely, you created a short from out to ground when you connected the cap. Bob
  12. BobK

    Guitar pedal that records noise and compresses it into an effect

    Yes, it is called a sampling synthesizer. They can record a sound and then play it back at different frequencies. Bob
  13. BobK

    ground issues with switching batteries

    What exactly is it that you are you trying to do? Why can't you simply connect the batteries in series and then have a single switch between them and the load (either high side or low side). Are you trying to switch the batteries from being in parallel to being in series? Bob
  14. BobK

    How is IOT different from Embedded Systems?

    It's all about the buzzwords. Bob
  15. BobK

    LM317 2N3055 Variable Circuit Problems

    Hey, I live in Worcester. But I think my Worcester is about 3000 miles from your Worcester. Bob
  16. BobK

    LM317 2N3055 Variable Circuit Problems

    I am beginning to feel young, I am only 1.6 x 40 years old :) Bob
  17. BobK

    555 output to transformer failure

    TI has an excellent tool (that they inherited from National Semiconductor when they bought them out), called Wbench Designer. It is a free web based app that will design a boost converter (among other things) based on your input of requirements and their parts. I used it to design a boost...
  18. BobK

    LM317 2N3055 Variable Circuit Problems

    That appears to be wired correctly. The only way it is burning the pot is if either the resistor or the LM317 is shorted. Try it with a 1K resistor instead of the pot. You should get about 5.8V out if everything is working correctly. And if you burn the 1K resistor, it must be that the power...
  19. BobK

    Microcontroller project for my pool pumps

    I told you so, several posts back. That was the only thing that made sense, given your readings and the description of the behavior. Bob
  20. BobK

    LM317 2N3055 Variable Circuit Problems

    Also, audio output is easy to achieve but hard to suppress in that type of device. Bob
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