Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations MintJulep on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  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
  16. dspDad

    super cap charging dilemma

    You also need to bypass the two caps to equalize leakage, otherwise the voltages will not be equal and you'll destroy one or the other of them. You might also consider whether your supply will tolerate overcurrent or a short for 10 seconds. Most of them are fairly happy. The uProcessor may...
  17. dspDad

    Why is 110V safer than 220V?

    The typical skin impedance when dry is in the megohms, but when wet and/or abraded, is closer to 1000 ohms. This allows 100 mA or so at 110 and about twice that at 220. It takes about 5 mA to cause tetany, and 5 mA hurts, and it takes about 20 mA to get 'glued' to the wire. The current density...
  18. dspDad

    Digital to Analog conversion? DAC0832?

    The DAC0832 is a pretty simple chip. Check every pin for power, ground, vref and appropriate selects (active low for cs, wr and others) It has a 'pass through' mode if all the selects are tied low. Once you see anything at all, you can work backwards. I would ask Melone's question, how do...
  19. dspDad

    Missing solder point on pcba assembly.

    Visual inspection is much superior to any functional testing method if your failure is missed solder points. If this is a production process, consider wave-soldering which has other failure modes, but missed points is not among them. Another thought is to get your manual processes under...
  20. dspDad

    PCB layout DC-DC convertors

    CircuitDesignExpert has the right approach. I would additionally make sure the power and return lines to the dc-dc convertor feeding the analog section is separated from the power and signal paths used by the analog section. Good luck. DspDad

Part and Inventory Search

Back
Top