---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 12/29/16: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:12 AM - USB (BobbyPaulk@comcast.net) 2. 06:13 AM - Re: Re: 5 Volt Converter Product Review (rnjcurtis) 3. 07:49 AM - Re: USB (Robert L. Nuckolls, III) 4. 08:03 AM - Re: Re: 5 Volt Converter Product Review (Eric Page) 5. 08:47 AM - Solder-sleeves with pigtails (Robert L. Nuckolls, III) 6. 02:29 PM - Re: A couple of questions about Fuses (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 05:12:44 AM PST US From: BobbyPaulk@comcast.net Subject: AeroElectric-List: USB Guys I have noticed some USB ports will charge a Samsung or other device and not an I-phone or other I-thingy. Is one available that wold do both or do I have a faulty port. Bobby analog guy in a digital world ________________________________ Message 2 _____________________________________ Time: 06:13:23 AM PST US Subject: Re: AeroElectric-List: Re: 5 Volt Converter Product Review From: rnjcurtis QW0gSSBjb3JyZWN0IGluIGFzc3VtaW5nIHRoYXQgaWYgSSB3aXJlIGEgVVNCIHBvcnQgdGhpcyB3 YXkgZm9yIGFuIEFwcGxlIGRldmljZSwgdGhhdCBpdCB3aWxsIGJlIGNvbXBhcmFibGUgd2l0aCBh bGwgb3RoZXIgQW5kcm9pZCBkZXZpY2VzLgoKUm9nZXIKCgoKU2VudCBmcm9tOiBZT0dBIFRBQkxF VCAxMCBIRCsKCkVyaWMgUGFnZSA8ZWRwYXY4ckB5YWhvby5jb20+IHdyb3RlOgoKPkludGhlZm91 cnllYXJzc2luY2VJd3JvdGV0aGF0LEFwcGxlaGFzcmVsZWFzZWRhZm91cnRoY2hhcmdpbmdzY2hl bWVmb3J0aGVpcjEyLXdhdHQoNVYsMi40QSljaGFyZ2Vyc3RoYXRiZWdhbnNoaXBwaW5nd2l0aHRo ZWlQYWRBaXIuSWZ5b3Vjb25maWd1cmV5b3VyVVNCcG9ydGFzZm9sbG93cyxpdHdpbGxyYXBpZC1j aGFyZ2VhbGxidXR0aGVlYXJsaWVzdEFwcGxlaURldmljZXM6UGluMSgrVik6NS4wVi01LjJWUGlu MihELSk6Mi43NVZQaW4zKEQrKToyLjc1VlBpbjQ6R3JvdW5kTm90ZXRoYXRQaW5zMmFuZDNhcmV0 aGVzYW1ldm9sdGFnZSxidXR0aGV5bXVzdCpub3QqYmVzaG9ydGVkdG9nZXRoZXIuVXNldHdvaWRl bnRpY2Fsdm9sdGFnZWRpdmlkZXJzdG9wcm92aWRldGhlc2FtZXZvbHRhZ2V0b2JvdGhwaW5zc2Vw YXJhdGVseS5Gb3J0aGV2b2x0YWdlY29udmVydGVydGhhdEpvZXB1cmNoYXNlZChvdXRwdXQ9NS4x ViksSXdvdWxkdXNlYXZvbHRhZ2VkaXZpZGVyY29tcHJpc2Vkb2YxMS44a292ZXIxMy43ay5Db25u ZWN0YXNmb2xsb3dzOjVWLS0xMS44ay0tVVNCUGluMm9yMy0tMTMuN2stLUdyb3VuZFN1aXRhYmxl cmVzaXN0b3JzOmh0dHA6Ly93d3cuZGlnaWtleS5jb20vcHJvZHVjdC1kZXRhaWwvZW4veWFnZW8v TUZSLTI1RkJGNTItMTFLOC8xMS44S1hCSy1ORC8xMzIzMi1hbmQtaHR0cDovL3d3dy5kaWdpa2V5 LmNvbS9wcm9kdWN0LWRldGFpbC9lbi95YWdlby9NRlItMjVGQkY1Mi0xM0s3LzEzLjdLWEJLLU5E LzEzMjQ0T25lb3RoZXJub3RlLlVzZWhlYXZpZXJ3aXJlb250aGU1Vm91dHB1dHRoYW50aGVjaGFy Z2luZ2N1cnJlbnR3b3VsZG5vcm1hbGx5Y2FsbGZvci5SZXNpc3RpdmV2b2x0YWdlZHJvcGNhbmVh c2lseWNhdXNldGhlNVZyYWlsdG9mYWxsYmVsb3c1Vm92ZXJhbW9kZXN0d2lyZWxlbmd0aCx3aGlj aHdpbGxjaGFuZ2V0aGVEK2FuZEQtdm9sdGFnZXNhc3dlbGwuQXBwbGVkZXZpY2VzYXJlcGlja3kt LWl0J3NpbXBvcnRhbnR0aGF0K1YsRCthbmRELWFyZWNvcnJlY3QuRXJpY09uRGVjMjgsMjAxNixh dDg6MTFQTSx1c2VyOTI1M2ZyYW5zZXdAZ21haWwuY29td3JvdGU6UmVhZHRoaXNwb3N0YWJvdXRj aGFyZ2luZ2FuaVBhZDpodHRwOi8vd3d3Lm1hdHJvbmljcy5jb20vZGlnZXN0L2Flcm9lbGVjdHJp Yy1saXN0L0RpZ2VzdC5BZXJvRWxlY3RyaWMtTGlzdC4yMDEyLTA5LTE3Lmh0bWwjTUVTU0FHRTdU aGVyZW11c3RiZXZvbHRhZ2VvblVTQnBpbnMyM3Rvc2lnbmFsdGhlaVBhZHRvZHJhd21vcmVjaGFy Z2luZ2N1cnJlbnQuVXNlYXZvbHRhZ2VkaXZpZGVyd2l0aG5vcmVzaXN0b3JsZXNzdGhhbjEwS29o bS5CZWxvd2lzcXVvdGVmcm9tdGhlYWJvdmVtZW50aW9uZWRwb3N0OkhlcmUnc3doYXR5b3VyVVNC cmVjZXB0YWNsZW5lZWRzdG9wcm92aWRldG9wcm9wZXJseXF1aWNrLWNoYXJnZXlvdXJpUGFkKGZv cmlQaG9uZXMscmV2ZXJzZXBpbnMyYW5kMyk6UGluMSgrVik6NVYobm9sZXNzO2lkZWFsbHl+NS4y VilQaW4yKEQtKToyLjAwVlBpbjMoRCspOjIuNzVWUGluNDpHcm91bmQ ________________________________ Message 3 _____________________________________ Time: 07:49:08 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: USB At 07:11 AM 12/29/2016, you wrote: Guys I have noticed some USB ports will charge a Samsung or other device and not an I-phone or other I-thingy. Is one available that wold do both or do I have a faulty port. There are USB ports . . . and then their are USB ports. The legacy USB port was conceived as a bi-directional, serial data port for SMALL accessories like thumb drives, mice, keyboards, etc. Power supplied from this port was offered at rather small rates . . . 100 to 500 milliamperes. Many computers were fitted with positive temperature coefficient current limiters (poly-fuses) to protect the computer from damage should the +5 volt USB power line become overloaded. Years later, new kids on the block (phones, tablets, etc.) found it useful to exploit that handy source of regulated voltage to charge internal batteries while in communication with a host computer . . . or even as a low-power charging source where leaving one's device on-charge overnight was no big deal. Simultaneously, demands on performance for USB ports evolved with ever higher transfer speeds. Accessories that exploited USB ports also evolved . . . there are electro-mechanical hard drives that will function solely on a 5 volt power supply while demanding less than 500mA. Then came the big kids. Tablets and larger smart phones that communicate with other devices via, you guessed it, USB ports. At he same time, their energy needs for both function and battery charging grew to 3 or 4 times that which the computer-based USB port could provide. This gave rise to proprietary chargers capable of 1 amp or more of 5v power. Problem was that if you configured your mini-super-pc to demand say 2A of battery recharge current, how do you keep it from overwhelming the 5v source on a legacy USB computer port? Instead of 'smart source ports' on computers, high-demand appliances evolved into 'smart-loads'. When the USB port was being used for only functional and/or battery charging power, then idle data lines could be used to tell the smart load how much power was available. Over the years, proprietary chargers lead the way to mostly accepted standards for tying idle data lines to each other or perhaps tying them to +5 or ground with certain size resistors. This little hat-dance in the source connector informed smart-loads as to how much energy was available. I have at least one device that annunciates "slow charging" behavior when plugged into a computer . . . with no such annunciation when being powered with a high-current source. The SHORT story in this thread tells us that it is insufficient to simply craft robustly powered, panel-mounted USB receptacles with an expectation of maximizing exploitation of that source. I've not taken time to study USB charging philosophies in detail but know that there is a lot of data on the techniques available on the 'net. It's a sure bet that any DIY power sources for your favorite cockpit companion may need a bit more information as to who much power is available. lacking such information will most certainly force the appliance into a 'slow charge' mode. Bob . . . --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 4 _____________________________________ Time: 08:03:02 AM PST US From: Eric Page Subject: Re: AeroElectric-List: Re: 5 Volt Converter Product Review I'm not sure what an Android device (a generic term for devices from many ma nufacturers) will make of an Apple charger. It won't do it any harm, but I d on't know if it will charge. Samsung, for example, uses a common (shorted) 1 .25V on both data pins. Someone mentioned that the data pins on his charger are shorted together. T hat defines a Dedicated Charging Port (and a Chinese standard). Most device s will accept this scheme, but will only draw 0.5A in accordance with the US B standard. That's why a device will hold steady under use but not add char ge. There are integrated circuits designed for this purpose that monitor a USB p ort and automatically configure the port to satisfy the device that's plugge d into it. They work fine, but they're a pain to use as they're all in tiny surface-mount packages. Eric > On Dec 29, 2016, at 7:11 AM, rnjcurtis wrote: > > Am I correct in assuming that if I wire a USB port this way for an Apple d evice, that it will be comparable with all other Android devices. > > Roger > > > > Sent from: YOGA TABLET 10 HD+ > > Eric Page wrote: > > In the four years since I wrote that, Apple has released a fourth charging scheme for their 12-watt (5V, 2.4A) chargers that began shipping with the i Pad Air. If you configure your USB port as follows, it will rapid-charge al l but the earliest Apple iDevices: > > Pin 1 (+V): 5.0V-5.2V > Pin 2 (D-): 2.75V > Pin 3 (D+): 2.75V > Pin 4: Ground > > Note that Pins 2 and 3 are the same voltage, but they must *not* be shorte d together. Use two identical voltage dividers to provide the same voltage t o both pins separately. > > For the voltage converter that Joe purchased (output = 5.1V), I would us e a voltage divider comprised of 11.8k over 13.7k. > > Connect as follows: 5V --> 11.8k --> USB Pin 2 or 3 --> 13.7k --> Ground > > Suitable resistors: > http://www.digikey.com/product-detail/en/yageo/MFR-25FBF52-11K8/11.8KXBK-N D/13232 > -and- > http://www.digikey.com/product-detail/en/yageo/MFR-25FBF52-13K7/13.7KXBK-N D/13244 > > One other note. Use heavier wire on the 5V output than the charging curre nt would normally call for. Resistive voltage drop can easily cause the 5V r ail to fall below 5V over a modest wire length, which will change the D+ and D- voltages as well. Apple devices are picky -- it's important that +V, D+ and D- are correct. > > Eric > > >> On Dec 28, 2016, at 8:11 PM, user9253 wrote: >> Read this post about charging an iPad: >> http://www.matronics.com/digest/aeroelectric-list/Digest.AeroElectric-Lis t.2012-09-17.html#MESSAGE7 >> There must be voltage on USB pins 2 & 3 to signal the iPad to draw more c harging current. Use a voltage divider with no resistor less than 10K ohm. Below is quote from the above mentioned post: >> >>> Here's what your USB receptacle needs to provide to properly quick-charg e your iPad (for iPhones, reverse pins 2 and 3): >>> Pin 1 (+V): 5V (no less; ideally ~5.2V) >>> Pin 2 (D-): 2.00V >>> Pin 3 (D+): 2.75V >>> Pin 4: Ground ________________________________ Message 5 _____________________________________ Time: 08:47:48 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Solder-sleeves with pigtails Some time back, I had a fire-sale on solder-sleeves . . . Demand was more than I could supply. Ran out in about a week. For those who were left wishing, here's an offer at MPJA http://tinyurl.com/grp3z2c Bob . . . --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 6 _____________________________________ Time: 02:29:16 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: A couple of questions about Fuses Some time back I wrote: >When selecting wires and protection, you're >never wrong with the "legacy pairs" of >22AWG/5A, 20AWG/7A, 18AWG/10A, etc. etc. >These are very conservative pairings. I thought of a quality unique to fuses that justifies a departure from the 'leggacy pairing' cited above. Fuses and Circuit breakers have one thing in common . . . they operated based on the HEATING effect of a current flowing in a component having some resistance . . . I.e. a voltage drop that liberates heat due to 'lost' energy. The similarity ends there. Circuit breakers have bi-metal components which are close cousins to thermostats. Heating produces a change in shape that causes some latching mechanism to release at a predictable temperature rise. On the other hand, the resistive current sensing component of a fuse is solid metal alloy designed to MELT when a certain temperature is reached. Conversion from a SOLID to a LIQUID calls for a phase change that exhibits a kind of plateau that cannot be exceeded until a unique quantum of heat has been delivered into the mass. In water, the heat removed in the change of phase from liquid to solid is called the 'heat of fusion' and if memory serves, is about 80 cal/gm for water. This means that you can have ice at 0C and water at 0C . . . but for every gram of ice at 0C you have to pump 80 cal of heat into it just to convert to liquid water. Every material, including the melting link in a fuse has a similar characteristic. This is important in the specification of fuses to a particular task. While a circuit breaker is a simplified 'thermostat' . . . capable of repeated operations with no change of calibration. On the other hand a fuse can, if you will, be 'hammered'. Let's say you have a 5A fuse loaded to 4A but subjected to an 8A transient measured in tens of milliseconds. On the bench you can subject the fuse to this stress many times with no failure. Such an event, say once per flight cycle in an airplane, may never produced a nuisance trip . . . or it may happen after tens or hundreds of flight hours. It doesn't happen very often, but ONE TIME may be too many for individuals who suffer the event. An excellent case in point . . . http://tinyurl.com/msfmldj Through a combination of events and poor design choices, fuses in the accident aircraft were subject to transient stresses that 'hammered' at the edge for heat-of-fusion on first one and then the second of two fuses . . . a failure that insured simultaneous failure of both ignition systems. The point to be pondered here illustrates the value of failure mode effects analysis in deducing risks associated with the failure of any single component. When unacceptable risks are identified, changes to selection components and system architecture will easily negate the risk. THE BEST prophylactics against risk for popping a 'hammered' fuse is to design the system such that loss of that system is no-big-deal. After all, there a dozens of OTHER reasons the fuse might open. Be prepared for ANY event. Based on what we know about the relative fragility of a 22AWG wire, a 5A, nuisance tripping fuse on a 22AWG feeder can be comfortably replaced with a 7A fuse. As a general rule, the engineering data on fuses suggests they not be continuously loaded to more than 75% of rating at 25C. http://tinyurl.com/zobgmdv If situated in an environment routinely hotter than 25C, perhaps de-rating to 50% is in order. This thinking supports the notion that a fuse under the cowl driving a 22AWG feeder loaded to 4A continuously might be 'protected' at 10A. It's not radical thinking . . . they do this in cars all the time. Bob . . . --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.