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  1. BobK

    Mosfet noob

    Are you sure the pulldown was 5K? It sounds like it was a bit smaller. And 5K is not a standard resistor value. Bob
  2. BobK

    Simplest and cheapest possible noise generator circuit

    Well the simplest sound to make is, as CocaCola already said an oscillator. This puts out a sound of a specific frequency. An oscillator circult could easily be designed to have it's frequency controlled by resistance of a human touching two conductors. A '555 timer would do this easily. Bob
  3. BobK

    Simplest and cheapest possible noise generator circuit

    Noise in electronics has a very different meaning from what I think you are looking for. Think of an FM radio tuned between stations. This is what electronic noise sounds like. Is this what you mean, or something else?
  4. BobK

    Playing a sound clip

    Google "sound recording module". Bob
  5. BobK

    Chronograph for bullets

    The only loss of energy would be as heat (from the friction of bullet entering the wood.). I have no idea how much that would effect the result. My gut feel is that it is small enough to ignore. Bob
  6. BobK

    Ohm's Law or not Ohm's Law... That is the question

    Yep, you just take the Laplace transform of it and it gives you a differential equation that, when solved gives you a complex exponential. This is certainly just as simple as E = I R Bob
  7. BobK

    Mosfet noob

    That circuit should work. Very strange, though: I scrolled through the datasheet 3 times and cannot find anywhere where it specifies which pin is which. How did you decide which pins are the s d and g? Bob
  8. BobK

    Led wiring.

    You could try reading this: https://www.electronicspoint.com/got-question-driving-leds-another-work-progress-t228474.html Oh, and welcome to the forum! Bob
  9. BobK

    How can I count analogue pulses over 10secs.

    It comes down to more hardware or more programming. The choice is yours. I am probably biased because my current job is working on a program with >1M lines of code, so software complexity might not be as intimidating to me as it would be to you! Bob
  10. BobK

    More current and less voltage?

    And if what you mean is what would happen if I run a 12V fan at 6V, it would probably draw less current and run a lot slower, or possibly draw more current and not run at all. Bob
  11. BobK

    Ohm's Law or not Ohm's Law... That is the question

    Yes, and if that is what everyone meant by Ohm's law, you would be correct. Of course the simplicity of this equation is hiding the fact that it indeed a differential equation, not a simple proportionality of I to V. Bob
  12. BobK

    a push in the right direction

    What you probably want is a single board computer. This could be an ARM chip or X86 chip running Linux. Bob
  13. BobK

    Choosing between photodiodes and phototransistor designs for a amplification circuit.

    Are you sure that a fire is putting out a lot more IR energy than a hot element? After all, you can ignite paper of the hot element easily, so its temp is higher than the flaming paper. I do not know how much IR at what wavelengths either of these would put out, but I would bet that it would...
  14. BobK

    Choosing between photodiodes and phototransistor designs for a amplification circuit.

    An IR remote works by modulating the signal at the sender. The receiver can then check for the specific modulation frequency and ignore other background that is orders of magnitude higher. Unless you can convice your fire to oscillate at 40KHz, this method is not going to work for you. The...
  15. BobK

    How can I count analogue pulses over 10secs.

    Personally, I would stick with the ADC since you already have the microcontroller, why add extra hardware? What you have to do is wait for the signal to go above a certain level, count a pulse, then wait until it goes below another lower level before looking for the next pulse. This emulates a...
  16. BobK

    Ohm's Law or not Ohm's Law... That is the question

    CDRIVE, I have not enaged in any personal attack, or at least none was intended. I have attacked only your statement that "all components obey Ohm's law." I did say that the statement is ridiculous, which might be a bit overstated, but please understand this is light of the fact that pretty...
  17. BobK

    Ohm's Law or not Ohm's Law... That is the question

    This is exactly my point. Proportional is key word. The current in an inductor or a capacitor is not proportional to the voltage. Here is the equation that fully describes the relationship of the voltage to the current in an indcutor: E = L dI/dt The voltage is proportional not...
  18. BobK

    Ohm's Law or not Ohm's Law... That is the question

    And that Generalized Ohm's law (which is not Ohm's law) applies only in the case the voltage is a sine wave of a specific frequency, that is why w (or f) is a part of that equation. How does The inductor obey the generalized Ohm's law in response to a step function? What is the constant R that...
  19. BobK

    Ohm's Law or not Ohm's Law... That is the question

    And that Generalized Ohm's law (which is not Ohm's law) applies only in the case the voltage is a sine wave of a specific frequency, that is why w (or f) is a part of that equation. How does The inductor obey the generalized Ohm's law in response to a step function? What is the constant R that...
  20. BobK

    Ohm's Law or not Ohm's Law... That is the question

    Please show me the post where I insulted you. I did no such thing. I questioned your statement that "all components obey Ohm's law". Your very first post after that came across as combatative. Bob
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