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  1. BobK

    Easiest method to convert analog ac voltage or frequency to digital 0-5v dc?

    Depends on the voltage, a rectifier would need a signifcant fraction of a Volt before it would conduct. Bob
  2. BobK

    Current Operated Relay

    Ah, okay, now it makes more sense. Bob
  3. BobK

    Creationism/Intelligent Design

    Electronics is, by far, the outlier in improvement and cost reduction. If medical technology had taken the same path, there would be no reason to argue about the costs of care. Instead it becomes ever more costly. And, IMHO, world politics is making negative progress. Interesting comment...
  4. BobK

    Current Operated Relay

    It is not at all obvious. What you are doing is very odd. One does not normally put a load, dummy or otherwise, in series with a relay coil. To prove the operation of a relay, the indicator (not dimmy load) would be in series with the relay contacts, not the coil. And the resistor for an...
  5. BobK

    Creationism/Intelligent Design

    "Play that funky music white boy..." Bob
  6. BobK

    Creationism/Intelligent Design

    Theoretically, I see no reason to reject the possibility. But practically, I don't think humans will survive long enough to achieve it. Bob
  7. BobK

    Multimeter reading of LED

    But the forward voltage of a diode or LED depends non-linearly on the current through it. As I stated before, your multimeter is measuring the forward voltage of your LED at some unspecified current. It is not measuring the forward voltage at the rated operating current, which is the number...
  8. BobK

    Current Operated Relay

    This thread is labeled "current operated relay". I don't see any relays in your schematic. I don't see any load requiring 180mA in you schematic. Why are you are wasting our time by keeping information from us? Bob
  9. BobK

    Op Amp with a/c output

    Yes, assuming the the sensor has metallic contact with the chassis, the ground could come from there. But I still suspect that the it is really a coil. Bob
  10. BobK

    Multimeter reading of LED

    It is the forward voltage at some current, not the operating current of the LED. The multimeter will apply a very small current to a diode under test, so the voltage reading will be way lower than the forward voltage at say 20mA, or at 1A or more that might be the operating current of a high...
  11. BobK

    Current Operated Relay

    Why an LED? If you want a load in the range of 300-400 mA, use a 40W bulb. Please explain more about what you are truing to do. Where does rhis relay coil enter into it? Bob
  12. BobK

    Thermometer Circuit

    If this is a school project, aren't you supposed to do the work, or at least understand the circuit that you "borrow?" Bob
  13. BobK

    Op Amp with a/c output

    Both of those understadings are wrong. If it is a hall effect sensor, one wire must be to the 12V power, and the other is the signal out. If it is a coil, it is truly putting out AC , and , to duplicate the original signal exactly, you would need an isolated, bipolar supply. But, based on...
  14. BobK

    Thermometer Circuit

    There is nothing mysterious about a window comparator. It is just one comparator for the high end and one for the low end. Using a standard comparator IC with open collector outputs, the two outputs can be wired together to a single pullup resustor to give a low signal when out of range and...
  15. BobK

    Spinning/rolls count device

    But he also said: "i want it to work with some gyro on the center of the wheel " Which I interpreted as using a gyro sensor, which he confirmed later when he linked to exactly that. Bob
  16. BobK

    Frequency and time confusion

    Actually, AK's example is the perfect example of why you must think both in terms of time and frequency. Suppose you need to measure a frequency. Let's say it is in the region of 1 MHz. Your micro will not be fast enough to measure the time between consecutive cycles. The way you do this is...
  17. BobK

    Project suggestions

    Read sagation and sagetion as suggestion. Bob
  18. BobK

    Spinning/rolls count device

    Who said anything about a spinning top? In the OP he is talking about a wheel. He mentioned a gyro, as a sensor, and everyone seems to think he is talking about measuring the rotation of a spinning gyroscope. The gyro he refers to is a chip that senses angular rotation speed, not a spinning...
  19. BobK

    Can Power Supply Sink Current

    A diode between the power supply and the motor. Bob
  20. BobK

    Easiest method to convert analog ac voltage or frequency to digital 0-5v dc?

    An increasing field produces a voltage in one direction, a decreasing field produces a voltage in the opposite direction. So, unless your field is always increasing, or always decreasing, it will produce both positive and negatve voltage. Bob
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