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  1. BobK

    Record player motor voltages

    No, that is not what is meant by shielded cable. Shielded cable has and outer mesh of metal for the ground connection and an inner connecter (shielded by the metal mesh ground) for the signal. Bob
  2. BobK

    Control for Speaker

    Like what kind of sounds. Do you mean simple beeping sounds that might be created by your micro, or recorded sounds like and MP3? Bob
  3. BobK

    Microwave inverter project

    And there are physical limits on how small and light a transformer for 50/60 Hz can be. They don't just make them big and heavy because they fell like it. This is because many windings are required to have enough inductance at low frequencies to overwhelm the resistance. And inductance...
  4. BobK

    Measuring the speed of a Frisbee & Boomerang

    Agree. I think we call can agree that the centripetal acceleration can be measured and the rotational speed calculated from it. Bob
  5. BobK

    Measuring the speed of a Frisbee & Boomerang

    The velocity is changing as you say, but I believe the acceleration is still toward the center of the of wheel. Think of the rate of change in the tangential velocity. It is zero when at the top or bottom of your catenary curve and highest when at the midpoints between them. This is...
  6. BobK

    Measuring the speed of a Frisbee & Boomerang

    Works best on sunny days not at noon! Bob
  7. BobK

    Measuring the speed of a Frisbee & Boomerang

    I think it is over all of our collective heads. On third though, I though Steve might be right, but for a different reason than I originally was thinking of. Consider the Frisbee to be a uniform disc (or at least radially symmetric). When rotatating, any point on the disc, other than the...
  8. BobK

    Measuring the speed of a Frisbee & Boomerang

    No, don't be sad, because it does not work. I was thinking of the sensor being in the same orientation throughout the revolution, but it is not, it rotates with the Frisbee. So the acceleration would actually read 0 at all times. I posted without thinking it through all the way. Bob
  9. BobK

    How to design a Flip Flop using 555 Timer ?

    That is not the usual terminology. A flip flop is a bistable multivibrator. There are also monostable and astable multivibrators, but not monostable and bistable flip flops. Bob
  10. BobK

    Circuit board design project

    I seriously doubt that. Bob
  11. BobK

    Measuring the speed of a Frisbee & Boomerang

    You don't need the equation. An accelerometer configured to read the acceleration tangential to the rotation would put out a sine wave at the frequency of rotation. All you would need to do is measure that frequency, and it would be very accurate. Bob
  12. BobK

    Change the color of an LED strip to white(without controller)

    Yes, that is why I asked my question. Bob
  13. BobK

    Microwave inverter project

    Transformer? Bob
  14. BobK

    Change the color of an LED strip to white(without controller)

    What color does it make when you power all three of the RGB inputs? Bob
  15. BobK

    Schmitt Trigger

    You could probably use a Schmitt trigger CMOS gate. What voltage are you using for supply? Bob
  16. BobK

    Hello, Newbie here. Power Question

    Wear ear protection! Bob
  17. BobK

    energizing fans

    Since 1 HP is 745W, your fans should be somewhere around 745/16 = 46W. And you say they take 10A at 115V = 1150W? That is quite an inefficient fan. Are you sure is not 1.0A? Bob
  18. BobK

    Circuit Help

    A matrix like that will work only if you can only have one row and one column switch on at a time. To make this work, you need an AND gate for each LED. Each of the switches produces a HIGH when ON and LOW when OFF. The LED is the AND of the signals from the two switches that intersect it in...
  19. BobK

    Serious lead-acid battery charger

    I have never heard of lead acid batteries with1.2V per cell, they are normally 2.0V per cell. This sounds more like NiCad or NiMH. Bob
  20. BobK

    Opamp help

    This sounds like homework. The way to analyze op amp circuits is to determine an equation for the + input and one for the - input. To a good approximation, these will be equal, because, if not, the difference will be multiplied by 1,000,000 or more and sent to the output, which will put the...
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