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  1. BobK

    Need help with re connecting some speakers

    Or look in my basement. I must have 1000 of them. Bob
  2. BobK

    Partially shaded solar panels

    Well, with the neutral well grounded on both sides... Bob
  3. BobK

    High Power Exclusive OR Gate Help

    A MOSFET can easily control a 2A motor, and if you choose a logic level one, it can be controlled directly from an Arduino. Bob
  4. BobK

    High Power Exclusive OR Gate Help

    Where did you get the idea that you need an XOR gate? Bob
  5. BobK

    Partially shaded solar panels

    Yes. A large statue of the blessed virgin, well lighted, in the back yard. Maybe what I need is a long extension cord Bob
  6. BobK

    Partially shaded solar panels

    But we like the shade, especially when sitting by our pond in the afternoon. Plus, the neighbor is an Italian Catholic priest. He is undoubtedly connected, to the mob or Jesus or both. Not messing with him! Bob
  7. BobK

    Solar cell charger

    When the input is insufficient, the regulator will put out a lower, unregulated voltage. Bob
  8. BobK

    Partially shaded solar panels

    Unfortunately, they are not on my property. Bob
  9. BobK

    Push Button H2O - Reversing Polarity

    Reading several descriptions of the this, I am totally convinced you do not have to reverse the polarity. Each pulse simply flips it from one state to the other. There is never a mention of reversing the polarity. I would be pissed if I bought this based on the description and it did not work...
  10. BobK

    Push Button H2O - Reversing Polarity

    Yes, I am going by what the link you posted said. Did you try to see if using the same polarity twice also might flip it? Because that is what I read the specs as saying. And, a normal solenoid pulls one direction no matter which way it is connected. But there are solenoids with a magnetized...
  11. BobK

    Solar cell charger

    I doubt that it would get damaged any more than it would get damaged if plugged into a mains powered charger and the power went off. But you might want to use a circuit that cuts it off completely when it cannot produce something close to 5V output. A continuous 2 or 3V might be handled badly...
  12. BobK

    op amp question

    When the + input is higher than the - input, the output goes up. So, with 1V on the + input and -2V on the - input, the output will be the max positive output voltage. However, you should never have a difference in voltage like that unless you are using the opamp as a comparator. For the...
  13. BobK

    Push Button H2O - Reversing Polarity

    Not really. You misunderstand. The pulse to open and the one to close are the same polarity. You do not need a two pole switch. Bob
  14. BobK

    Sound activated alarm

    Colin, you look less stupid if you read the entire post instead of just the title before responding. Bob
  15. BobK

    Help with component choice / design in an alarm circuit

    The on board "EEPROM" retains it's contents when the chip is powered off. That is the what distinguishes it from the RAM on board. There is no need for an external chip, which would only make the hardware and software more complicated. Bob
  16. BobK

    Push Button H2O - Reversing Polarity

    Well then, simply wiring a momentary contact switch to it will flip it with each press. Bob
  17. BobK

    Help with component choice / design in an alarm circuit

    I think pretty much all microcontrolles today use flash memory, not EEPROM, but that is unimportant since they pretty much do that same thing. Many have some flash data storage that you can write and will hold it's contents when powered off. This is where you would store the code. Others...
  18. BobK

    Designing Relaxation Oscillator

    That is a pretty good explanation, but I would stay away from electrons doing this or that. We abstract electron behavior into voltages and currents, think in terms of those. We don't care what the actual electrons are doing. When you say solve for the elements, that is ambiguous. You can...
  19. BobK

    Designing Relaxation Oscillator

    Ah, the old UJT. Haven't used one in about 50 years. Do you understand how this circuit behaves? If so, please describe it. Then tell us where you think you might place the LED. Then we can talk about how to control the timing and the current through the LED. Is that what you are asking...
  20. BobK

    Why DC motor draws more current with friction?

    If you are seeing even a few % change in your supply when drawing 500mA from a 10A capable supply, it is a pretty crappy supply. Bob
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