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Recent content by dspDad

  1. dspDad

    Safe To Touch Tests

    Safety is defined by the regulating authority for commerical applications, and is different for Europe, US, consumer grade, commercial grade and medical grade devices. Most of the agencies specify in detail how measurements are to be made. This includes leakage or voltage versus frequency, and...
  2. dspDad

    Strange problem with power loss

    Another thought is that the regulator is actually getting hot internally and going into thermal shutdown even though the outside of the case is cool because the airflow is high. Let us know what you find. DspDad
  3. dspDad

    Induced Voltage on Multi-Conductor Cable

    You probably have both capacitive and inductive coupling. You might also have the ir drop showing up. Twisted pair for each load will eliminate virtually all of these problems. If you had to pick one problem, the capacitive coupling will probably be the biggest problem. This will be...
  4. dspDad

    Nerve current timing

    Late response, similar to the measurements. Usually the nerve conduction velocity is measured over a fixed or measured distance. (for example, elbow to writst) Slowing and a change in the waveshape is indicative of injury. The number of neurons is much harder to measure, and until large...
  5. dspDad

    EEG measurement

    The MEG or magneto-encephalogram does that. Uses an array of supercooled magnetic pickups to measure brain electrical activity not only at the surface, but at depth. Dspdad
  6. dspDad

    Lightning damage to underground sprinkler system

    I can believe you might take out a controller, but it seems less likely to fry the cables running underground. Have you checked for gophers? DspDad
  7. dspDad

    Energy efficient air amplifiers

    Graviman, The high bypass uses jet power to turn a ducted fan, and achieves what I would call impedance matching. As a result, the thrust is higher and the speed is lower, so energy is conserved. This only works for 'low' speeds, but mach .8 is low compared to jet exhaust, so all commercial...
  8. dspDad

    am I designing a "soft line"

    Max, Your line will see almost no inductive element due to the transformers. There may be some inductive kick from the pump when you energize and de-energize it, but this will be reflected dumped back into the mains a mile away. Transients (other than the momentary voltage drop during startup)...
  9. dspDad

    am I designing a "soft line"

    Both the step up and the step down transformers have to be rated for the peak loads. The drop in the 4800 v line is probably not going to be significant. It would be less expensive to put a 1 kW battery backup at the house to maintain line voltage during the transient, or to ignore the...
  10. dspDad

    Energy efficient air amplifiers

    Does anybody know a non-mechanical way to convert high pressure (or high velocity) air flow to a larger mass of slower flowing air in an efficient manner. I am looking for a no-moving parts method of performing what a high-bypass fan does in a jet engine. So far I've tried a venturi type...
  11. dspDad

    Single Pull up/down resistor for multiple Pins

    There are two reasons for pullup/pulldown resistors. 1) If a chip has i/o on the same pin, you can exceed its current output rating if it is tied to ground and it is inadvertently enabled as an output. With most modern chips this is a non-issue, but 20 years ago it was a good way to destroy...
  12. dspDad

    Thread Detection

    If you can hit the hole with an eddy current probe or even a magnetic transducer, you should see large oscillations as it passes over the threads. A PLC would be able to discern the difference between a threaded and non-threaded item. This requires inserting a probe through the hole which is...
  13. dspDad

    super cap charging dilemma

    If you have a 25% duty cyle with a 4.6 msec repeat interval, then the caps are way too big (by a factor of 10000). Choose the cap size based on allowable voltage drop during the 1.15 msec 'on' time. I * delta time = C * delta voltage 250 uF would give you 0.1 volts drop. DspDad
  14. dspDad

    UV LED

    440-490 is blue, not UV. Do a search for 440 nM LED or Blue LED DspDad
  15. dspDad

    Thread Detection

    Whats a poke-yoke? Is this a metal part, ferro-magnetic or not, how big, how deep? Are the threads like pipe threads or machine-screw threads? DspDad
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