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  1. loicalset

    NEMA spec question - hazardous environments

    Wow, I guess we need to design a filling valve for the enclosure so that we can top it off with oil. Maybe a dipstick or something like that too... The spec is from our customer and believe me, we would like drop that requirement, as I don't think an oil filled enclosure will play nice with RF...
  2. loicalset

    NEMA spec question - hazardous environments

    Honestly! I can't believe they charge money for these things... The rest of the spec does not give any insight. Maybe I should try to find NEMA 8 equipment and see how it is being used. Thanks for the input, mac.
  3. loicalset

    NEMA spec question - hazardous environments

    Hello, I am looking to design a NEMA 8 enclosure and would like to know if anybody has experience with what exactly the spec means. I can't decipher if it means the electronics enclosure will be filled with oil or if it will be submerged in oil. Oil submersion makes more sense to me, but I...
  4. loicalset

    Need to invert voltage detector behavior

    Ah, yes I had considered the unstable behavior earlier. There is a bit of hysteresis built in to the comparator, and also the current draw is quite low compared to the resistance of the battery. But it is always good to keep these things in mind as you mentioned. And I wish I knew about that...
  5. loicalset

    Need to invert voltage detector behavior

    I have been searching through the Digi library for a while and have yet to find a reset IC that can take an input voltage over 7V (just noticed that the IC I poseted earlier has this limitation too). That is uncomfortably close to the max battery voltage. I think I will use a small n-fet to...
  6. loicalset

    Need to invert voltage detector behavior

    Possible solution... MAX810 active high reset monitor!
  7. loicalset

    Need to invert voltage detector behavior

    And please let me know if there is more information I can provide to help with solving the problem. Thanks.
  8. loicalset

    Need to invert voltage detector behavior

    Greetings, I have a voltage detector IC (Seiko) that outputs an active low (N-ch) as a result of a low voltage state (<5VDC). I also have a voltage regulator (LM2931) that can be turned ON via active low. The problem is that we would like the active low (which represents a low-battery or power...
  9. loicalset

    need UV stabilized, non brittle, clear, scratch resistant plastic

    Wow. That Lexan MR-5 looks amazing, but way out of my budget. I think I will give Arcylic or PC a shot. (It is a rugged application, so I think tempered glass is out). Thanks for the helpful information.
  10. loicalset

    need UV stabilized, non brittle, clear, scratch resistant plastic

    Thanks everyone!
  11. loicalset

    need UV stabilized, non brittle, clear, scratch resistant plastic

    Hello, I'm looking for a recommendation for a plastic cover for an array of solar cells. The main features that I understand to be important are: a. Scratch resistance (the unit will be used in rugged conditions) b. Non-yellowing c. UV stabilized - to protect the plastic from degrading in...
  12. loicalset

    cascaded N-mosfets

    Oops, yes I meant the TPS715. I think I may have found a suitable low quiescent LDO with a shutdown pin (LP2980-ADJ) to substitute for this part. Now, to locate a voltage supervisor that will go up to 7 volts input and detect a 5.2 volt crossing... but that's a topic for a separate thread...
  13. loicalset

    LOW BATTERY CUT-OFF, REVERSE POLARITY PROTECTION

    Just something to add (correct me if I am wrong): P type FETS require a 'negative' voltage in order to activate, which may be a problem depending on his circuit design. These would typically be used in a high-side switch (disconnect V+). N-type FETS require a 'positive' voltage and are...
  14. loicalset

    cascaded N-mosfets

    IRStuff - gotcha - that what was I was suspicious of but couldn't quite get my mind wrapped around. Thanks for the help.
  15. loicalset

    cascaded N-mosfets

    FYI, the LDO I was considering is the Texas Instruments TP715, because of the low quiescent current. Does somebody know off hand if this (p-FET) LDO would float high with its ground disconnected? I suppose the proper course of action now would be to find an LDO with a shutdown pin.
  16. loicalset

    cascaded N-mosfets

    I just realized that this may still be bad for the load device. Wow, time for bed probably.
  17. loicalset

    cascaded N-mosfets

    I love this forum. Thanks for the quick response. If the output floats high, there is still no way for the load to draw current without a ground connection, correct? The only worry would be damaging the LDO?
  18. loicalset

    cascaded N-mosfets

    A quick sanity check, because my brain is turning to mush: Is there any problem with using two cascaded N-MOSFETs as a sort of "AND" logic, low-side cutoff for an LDO regulator? I am planning to cascade them in the ground path of the LDO. There are two conditions (batt voltage good, mode...
  19. loicalset

    555 alternatives (long delay time)

    Perfect. Thanks for everyone's help!
  20. loicalset

    555 alternatives (long delay time)

    Ah ok. I will go back and reread the sheet. Thanks!

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