Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

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

Recent content by Foxfur

  1. Foxfur

    To SPI or to I2C...that is the question.

    I2C is a nice way to go, unless all devices that you need to communicate with do not have it. In that case, SPI is the winner as bit-banging will get you there. SPI is a simpler convention as it has just shift registers and a clock. I2C is somewhat (may be an understatement) overly complex...
  2. Foxfur

    Grouping Neutrals?

    Right-o Resqcapt19, "In some cases the grounded conductor of a multiwire circuit is inscreased in size over that of the ungrounded conductors for nonlinear loads." This is what we faced when wiring a new server room. SMPS's (in the servers and other computer equipment) are highly...
  3. Foxfur

    Hipot testing

    I'd think that 10 seconds would be a good place to start. Or you could do a destructive test on a unit or two just to establish the upper threshold. If this item is going to be marketed, a beefier unit that can stand up to relatively long hipot tests would stand out as a robust device. Longer is...
  4. Foxfur

    pcb hole diameter

    I'd size the holes about .005 over the wire diameter. If that doesn't land you on a fractional or numbered drill size, just round up to the next highest bit. if the holes are plated through, you will need to take the plating thickness into account when specifying the size. Foxfur
  5. Foxfur

    Self-threading (thread forming) screws

    If your company is determined to implement the use of thread forming screws, please make a suggestion on my (and many other end users) behalf. Where possible, make the hole a through hole (as on an overhanging flange) so that the original hole may be drilled out to the next screw size allowing...
  6. Foxfur

    Does anyone know were to get some h

    Hi Steveowens, Try: www.partsexpress.com (I know, the URL looks a little funny, but really, they're an electronics outfit!). I was just looking thru their catalog last night and am impressed with their selection. Another good hit is: http://www.l-com.com Amazing variety of cables and...
  7. Foxfur

    Relay driver circuit with timer

    Hi Ejaz, Take a look at Motorola's MC1455P. In fig 26 in the datasheet ( http://www.onsemi.com/pub/Collateral/MC1455-D.PDF ) it has a schematic for a sequential chain of timers. This still may not address your Iout requirement though, as the MC1455 has an abs max sink/source capability of 200mA...
  8. Foxfur

    Fluorescent tube questions

    In older mag ballasts, the dripping black glop collecting on the ballast cover is a darn good sign the ballast has had it. On the newer electronic ballasts, that all too familiar smell of fried electronics is the give away. I've never heard of that rule of thumb before. I've had ballasts be...
  9. Foxfur

    What is the effect of low temperatures on semiconductors

    Lithium is your best bet for sub-zero operation. I'm not sure of your definition of semiconductor. When you state "The semiconductor would have to act as a microprocessor..." it sounds as though you are asking for a PROM of varying flavors. Is it a "One-Chip" solution you...
  10. Foxfur

    Stepper motor plc Driven

    Here is a link that may help: http://www.ontrak.net/step.htm Another one: http://www.motiongroup.com/md.htm Here's one more (your best bet from my experience): http://support.automationdirect.com/technotes.html Look at the appnote (PDF format) on their D2-CTRINT ($73.00) module. It is used...
  11. Foxfur

    Self-rechargeable battery

    How about using an old bicycle generator (the one you'd flip down to touch the rear tire sidewall when the sun went down)? With one of these and perhaps an LM317T and some caps, methinks you might have a system. Rewinding the generator to suit your I & V needs could eliminate the needs for a...
  12. Foxfur

    Fuse failures

    Here's a good technical document outlining the analysis and testing of fuses in lo/no-G, vacuum, harsh environments. http://www.aem-usa.com/pages/press/OOPSC74.pdf Foxfur
  13. Foxfur

    Electronics Component Test Methods

    Here's a great FAQ on component testing: http://www.repairfaq.org/REPAIR/F_semitest.html Cheers, Ff
  14. Foxfur

    I need a stainless steel, potted, connector.

    http://www.glenair.com/ http://www.subconn.com/fronts.asp?active=products&prod=Metal_Shell Foxfur
  15. Foxfur

    Self-rechargeable battery

    Check out: http://www.techlib.com/electronics/stepper.html It has some info on using steppers as generators. If you make a large pulley for the stepper and use the shaft to drive it, it might get you there. I'd think about using a charge pump and regulator as well. Ff

Part and Inventory Search