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  1. BobK

    Switch question

    Which is the way a 3-way pickup switch typically works on a guitar. I am surprised the OP's has an off position in the middle. Bob
  2. BobK

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

    I am using the definition of Ohm's law that you will find on Wikipedia. It has 3 terms, I, E and R and R is a constant. It does not involve reactance which involves frequency. It deals with instantaneous I and V, not averages over a cycle like the generalized reactance equation. It does not...
  3. BobK

    Relation between the output volatage and the capacity of a battery

    Yes, there is none. Bob
  4. BobK

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

    Except that even that is not true. Here is a plot of your inductor circuit simulated: Note that the current is at the max when the voltage is zero. Let's take Ohm's Law: E = I R and rearrange it to: E / R = I Now, what is the R that will give you the correct I when E = 0? If it...
  5. BobK

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

    Ah, so now you have stooped to Ad-hominen via geography. By the way, what is it people don't like about Mass? Is the anti-intellectual response to to the fact the we have the highest scores on national tests, or is the anti-family values crowd that hates the fact the we have among the lowest...
  6. BobK

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

    That is like saying Einstein's general relativty equations are the same as Newton's law of gravitation. Bob
  7. BobK

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

    Chris, Please look up Ohm's law on Widipedia or somewhere. It is this equation: V = I R Where R is a constant. Inductive and capacitive reactance are not constants, they are frequency dependent. And the reactance analog of Ohm's law can only be stated in complex numbers. The...
  8. BobK

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

    Sorry Chris, but that is not Ohm's Law. Bob
  9. BobK

    Switch question

    The way I read that diagram, the center position is connecting both pickups and the outer positions are connecting one or the other. My guitar has a 5 position switch that blends the 2 pickups equally in the center, favors one or the other at next 2 outermost positions, and selects one or the...
  10. BobK

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

    What you are saying is that there is a analog to Ohm's law that applies, not the V = IR applies. Bob
  11. BobK

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

    The reactance model only works at a constant frequency, so even there it is not a universal law, it cannot be applied at all to changing, non-repetetive waveform. Ohm's law is universal law that states the dependence of voltage and current in an ideal resistor. To call anything else Ohm's law...
  12. BobK

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

    Yes, as a matter of fact it is a challenge. You cannot characterize an inductor, or a capacitor, or a diode, or a BJT or a MOSFET, or a JFET, or a neon light, or a DIAC or TRIAC or an SCR or any integrated circuit via Ohm's law. If something obeys Ohms law, it can be only one type of...
  13. BobK

    Taking the leap, breaking the Leap Pad

    You should also be aware that a programmable chiip in a commercial product is likely to be protected so that you cannot read or write to through the JTAG interface. Bob
  14. BobK

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

    That's news to me. Tell me how an inductor is governed by Ohm's law. Bob
  15. BobK

    LED driver

    Designing a mains powered switching power supply is no easy task, not one I would take on. Unless you have the experience to do this, you would be much better off either buying the switcher or using a transformer. Bob
  16. BobK

    Admiralty chart with LED sequences

    You could use and RGB LED at each site, but then you would have 3 times as many control signals. Bob
  17. BobK

    Choosing an IR photodiode or phototransistor for fire detection

    Perhaps an IR thermometer module would be better? Here is one example: https://www.sparkfun.com/products/9570 Bob
  18. BobK

    LTSpice simulator

    You need to check the box on the simulation options that says somehting like "start voltage sources at 0V" I don't remember the exact wording. LTSPICE solves for a steady state and many oscillators will just sit at that steady state instead of oscillating. The option makes it start the power...
  19. BobK

    reverse polarity

    I think he means the neutral / live reversed. If it is an outlet with a ground connection, you would want to put an indicator between the neutral and ground. If it lights, the polarity is reversed. Bob
  20. BobK

    Help me build a battery charger?

    Don't remove the coax cable from the connector, cut it, then splce the two wires to the shield and center wire. Do check the polarity though. Most likely the shield will be negative and the inner wire positive, but do make sure of this. Bob
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