Recent content by NeuronsAtWork

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    Can I Use PWM to Control My Electromagnet with a MOSFET and 12V Battery?

    Definitely need a diode across the coil for back EMF protection. Not usually a zener, just something like a 1N4004. See here: http://www.winpicprog.co.uk/graphics/relay_example.gif The MOSFET you spec'ed is rated 17A at 60V so should handle the current with a proper heatsink. (68 amp pulsed.)...
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    Is a fuel cell technically an energy storage device?

    I personally would not classify a fuel cell as an energy storage device, because unlike a battery it requires a constant outside source of fuel and oxygen to operate. A fuel cell can be one component of an energy storage device, but is not in and of itself in my opinion. As to your other...
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    Refrigerator Problem: Testing Compressor with 2 Wires & 3 Terminals

    Well, I see your point. Those ohm readings do sound somewhat high, but I have nothing here with which to compare them. As long as you aren't getting a direct short or an open odds are you are okay, though. The three contacts on the compressor (as you likely know) are S (start), R (run), and C...
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    Refrigerator Problem: Testing Compressor with 2 Wires & 3 Terminals

    I would not recommend trying to manually run the compressor in the way you suggest. The relay is a start relay; it briefly applies voltage to both the start and run windings of the compressor then opens and places the run capacitor in the circuit after the unit starts. It usually also contains...
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    Why Do Wind Turbines Have a Power Curve Limit?

    I'm not sure that the capability of the generator is necessarily fundamentally limited from an electrical output point of view, but may well be from a mechanical standpoint. Any generator--even a basic residential gas powered one--certainly has a maximum safe operating RPM, beyond which one runs...
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    Need controller like garage door opener

    Yes, I would think as far as the safety system they're probably all about the same. On mine it's called Safe-T-Beam. I have around a ten year old Genie basic opener--H4000-07. It's new enough to be the Intellicode style of remote, and says Series II electronics. I was actually able to locate the...
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    Need controller like garage door opener

    I'm not quite sure how you would get around the IR stuff. There are 2 screws, that are putting out some DC voltage to run the transmitter IR LED (plus the little LED on the side showing there is power) and then on the receiver there is another LED on the side that stays steady when the beam is...
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    Need controller like garage door opener

    Pretty cool--I didn't know you could pick up a board so inexpensively. To answer your question, the autoreverse logic does seem to be built into the board, in that if I stop the door halfway up with the button, then push the button again it will reverse (and vice versa). With that said, however...
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    Need controller like garage door opener

    There is stuff like this available: http://www.newegg.com/Product/Product.aspx?Item=N82E16881169010&nm_mc=KNC-GoogleAdwords&cm_mmc=KNC-GoogleAdwords-_-pla-_-NA-_-NA Also X-10 I know makes dry-contact relay devices for remote drape controls, etc. like this...
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    How to break down Dichlorodifluoromethane

    Chill Factor-- You got it. Phosgene, the nerve toxin, does not contain phosphorus. See the MSDS here: http://www.scottecatalog.com/msds.nsf/0/72d85a355ffe0cb785256a0a004e32fc?OpenDocument It can also break down into hydrochloric and hydroflouric acid, the latter being really bad news--I have...
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    How to break down Dichlorodifluoromethane

    Just a warning on this, as better to be safe than sorry. Please be aware that dichlorodifluoromethane decomposes into phosgene gas--a highly toxic and deadly nerve agent--at temperatures above about 1000 deg. F. Also free chlorine gas can be liberated under the right conditions as well. Please...
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    Medical How does the body know how much to sleep?

    I watched an interesting show on this subject a few years back. It followed a number of 'cavers'--scientists and geologists who would spend weeks underground exploring and mapping miles-long cave systems. They obviously had no conventional cycles of light and dark to influence waking and sleep...
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    How do telephone companies locate and repair broken wires in underground piping?

    Bobbywhy--it was my pleasure. Something else I found out--the reason they chose those particular colors was because those were the most common, longest lasting, and highest contrast fabric dye colors that existed at the time. All of the wire insulation was fabric, not plastic like today, so...
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    Why Do Star Trails Appear Denser on One Side of the National Geographic Photo?

    I'm sure Drakkith is correct--also the actual trails seem a bit overexposed, and that exacerbates the effect. I would guess that the photographer possibly 'stacked' multiple images and the alignment might have been off a bit, because the single exposure shots I've seen tend to be sharper...
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    NASA NASA Curiosity Rover Mars entry parachute deceleration question

    You know, I also thought after reading this that it be really interesting to see a graph like that. I looked everywhere--no joy. Maybe this would be a good question to fire off to Mohawk Guy at JPL. Surely they have the data...
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