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Barrel connectors

Started by Don Y November 15, 2013
On 2013-11-15, Don Y <This.is@not.Me> wrote:
> Hi, > > They're everywhere! > > And, often CRAP!
Sturgeons law?
> Any guidelines on selection criteria?
You mean like current limits and mating cycle counts?
> Any worries about failure modes?
The cable seems to die first in my experience.
> Do the "inverse" variety (now popular on laptops, LCD's, etc.) offer > any special advantages over the traditional style?
AFAICT three contacts. -- For a good time: install ntp --- news://freenews.netfront.net/ - complaints: news@netfront.net ---
Don Y <This.is@not.me> wrote:
> Any guidelines on selection criteria?
There is a Japanese standard for these, that Sony and Nintendo equipment seems to follow. http://en.wikipedia.org/wiki/EIAJ_connector The diameter goes up with voltage. The standard doesn't seem to require it, but it seems popular for the defined voltage to not be an even number. The insulator at the tips of these plugs is usually yellow, at least on Sony and Nintendo gear. For "regular" plugs, the most common OD is probably 5.5 mm, with either a 2.1 mm or 2.5 mm ID. The voltage and current can be anything at all, up to maybe 50 W, +/- 50 W. If you want your customers to be able to improvise a supply, pick a common size. If you want to sell them power supplies and/or cause them to go to the competition, pick a weird size. I don't know what brands are good or bad, but I'd probably look for a "name brand" like Switchcraft or Hirose first, and then look for something cheaper when the bean counters scream. A lot of smaller devices seem to have standardized on USB connectors, which are almost always good for 5 V, 0.5 A; higher currents are available but you can't always count on this. The main advantage is that you can be pretty sure that the voltage will be between 5.0 and 5.5 V, and that the polarity will be right.
> Any worries about failure modes?
I've actually had more failures of the wire right behind the plug than I have had of the plugs or the jacks. I would tend to trust a through- hole jack more than a surface mount one, especially if the plug will be disconnected and reconnected often. These are more of a design thing, but: one "failure mode" might be that if the plug even remotely sort of fits, people will try to cram it into the socket, so you might get all kinds of unexpected voltages coming in. A fuse with a "backwards" diode after it guards against wrong polarity; guarding against too-high voltage is a little trickier. If you can stand the voltage drop, board space, and budget, put in a bridge rectifier and a capacitor, so the user can use any AC or DC power supply of some minimum voltage. Also, some of the jacks have switches that open or close on plug insertion. Some devices use these to switch between internal or external power. Some users, though, might prefer to leave the plug connected all the time, and remove the AC power from the power supply instead; your device might not be able to rely on the switch contact in the jack.
> Do the "inverse" variety (now popular on laptops, LCD's, etc.) offer > any special advantages over the traditional style?
Are you talking about the ones that have a pin inside the barrel? As far as I know, this is to offer an extra "data" channel to the power supply; these are really 3-circuit connectors. The outside surface of the barrel is one side of the power supply (usually negative), the inside surface of the barrel is the other (usually positive), and the pin is "data". The "data" can be as simple as a resistor to one side of the power supply, which the connected device measures and interprets, or as complex as a serial bus to a microcontroller or ROM inside the power supply. The "data" can be used for good or for evil. A good use is that the cheap 20 volt 3 amp supply has (say) a 1K resistor to ground, and the more expensive 20 volt 5 amp supply has (say) a 2K resistor to ground. The connected device has an A/D that tells it what resistor is there, and then it can adjust its internal switching power supply appropriately to only draw as much current as the external supply is capable of. (Laptops often do this; they *have* to power the CPU and then the battery gets whatever is "left over".) An evil use is to require the power supply to authenticate to the connected device, in order to sell power supplies at inflated prices^W^W^W^W^W^Wprotect the consumer. Matt Roberds
Hi Matt,

On 11/15/2013 10:25 PM, mroberds@att.net wrote:
> Don Y<This.is@not.me> wrote: >> Any guidelines on selection criteria? > > There is a Japanese standard for these, that Sony and Nintendo equipment > seems to follow. http://en.wikipedia.org/wiki/EIAJ_connector The > diameter goes up with voltage.
Ah, OK.
> The standard doesn't seem to require it, > but it seems popular for the defined voltage to not be an even number. > The insulator at the tips of these plugs is usually yellow, at least on > Sony and Nintendo gear.
I've seen numerous colors: yellow, red, ubiquitous_black, etc. At first, I was excited thinking there might be some color code that would make sorting out what's what easier. But, that didn't pan out. So, a micrometer and selection of drill bits are my only real way of figuring out what the characteristics of a particular connector are.
> For "regular" plugs, the most common OD is probably 5.5 mm, with either > a 2.1 mm or 2.5 mm ID. The voltage and current can be anything at all, > up to maybe 50 W, +/- 50 W.
Great tolerance there! :>
> If you want your customers to be able to improvise a supply, pick a > common size. If you want to sell them power supplies and/or cause them > to go to the competition, pick a weird size.
I am more interested in understanding how/why particular sizes are chosen as there doesn't seem to be any sense to it all. It *seems* US firms have the barrel negative wrt center post. And, many far east firms the opposite. Except when they aren't! :<
> I don't know what brands are good or bad, but I'd probably look for a > "name brand" like Switchcraft or Hirose first, and then look for > something cheaper when the bean counters scream. > > A lot of smaller devices seem to have standardized on USB connectors, > which are almost always good for 5 V, 0.5 A; higher currents are > available but you can't always count on this. The main advantage is > that you can be pretty sure that the voltage will be between 5.0 and > 5.5 V, and that the polarity will be right.
Yes, but the connectors are more fragile and harder to mate.
>> Any worries about failure modes? > > I've actually had more failures of the wire right behind the plug than > I have had of the plugs or the jacks. I would tend to trust a through- > hole jack more than a surface mount one, especially if the plug will > be disconnected and reconnected often.
I've had to replace a number of jacks -- laptops, organs/"keyboards", etc. Usually devices that ither see lots of motion while in use *or* have heavy cords dangling off the connection, unsupported. I've also encountered broken "wipers" in the jack (the contact that mates with the O.D.) I figured connectors with a *longer* and *wider* barrel might be more mechanically secure -- not just because of the increased size but, also, because they could be more readily "supported" by bits of the device into which they mate (even if that support is non-conductive) I've also seen connectors that have quarter-turn locks built in. Insert and rotate to keep it from falling out (or being PULLED out)
> These are more of a design thing, but: one "failure mode" might be that > if the plug even remotely sort of fits, people will try to cram it into > the socket, so you might get all kinds of unexpected voltages coming in.
I think the biggest risk, there, is a "plug" with a "too large" I.D. being *apparently* mated to one with the correct O.D. but smaller I.D. -- not a very robust connection (if at all!)
> A fuse with a "backwards" diode after it guards against wrong polarity; > guarding against too-high voltage is a little trickier. If you can > stand the voltage drop, board space, and budget, put in a bridge > rectifier and a capacitor, so the user can use any AC or DC power supply > of some minimum voltage.
Exactly my thoughts (electrically). Let it feed anoher (set of) converters inside the device. More assurance that you have *all* the right supplies instead of HOPING to have the *one* right input supply.
> Also, some of the jacks have switches that open or close on plug > insertion. Some devices use these to switch between internal or > external power. Some users, though, might prefer to leave the plug > connected all the time, and remove the AC power from the power supply > instead; your device might not be able to rely on the switch contact > in the jack.
Ah, hadn't thought of that! Hadn't *planned* on such a connector, though. Worth remembering for future encounters!
>> Do the "inverse" variety (now popular on laptops, LCD's, etc.) offer >> any special advantages over the traditional style? > > Are you talking about the ones that have a pin inside the barrel? As
Yes. Looks sort of like the *mate* to the "original style" (hence my reason to call it "inverse")
> far as I know, this is to offer an extra "data" channel to the power > supply; these are really 3-circuit connectors. The outside surface of > the barrel is one side of the power supply (usually negative), the > inside surface of the barrel is the other (usually positive), and the
Ahhhhh! Yes, that makes perfect sense! I'd simply assumed the outside of the barrel was one conductor (like it had been for the "original" plugs) and the pin was there just to "be different". The larger diameter and length that typically are associated with these being mechanical "enhancements" -- e.g., laptops see a fair bit of motion reflected to that connection!
> pin is "data". The "data" can be as simple as a resistor to one side > of the power supply, which the connected device measures and interprets, > or as complex as a serial bus to a microcontroller or ROM inside the > power supply.
OK. Allows the PS to be "identified" by the device using it. Presumably, could also ensure the supply isn't powered up if t is "wrong"! Could also be used to power *down* the power supply when the device doesn't need it any longer! Or, could just be there to sell "special powersupplies" :-(
> The "data" can be used for good or for evil. A good use is that the > cheap 20 volt 3 amp supply has (say) a 1K resistor to ground, and the > more expensive 20 volt 5 amp supply has (say) a 2K resistor to ground. > The connected device has an A/D that tells it what resistor is there, > and then it can adjust its internal switching power supply appropriately > to only draw as much current as the external supply is capable of. > (Laptops often do this; they *have* to power the CPU and then the > battery gets whatever is "left over".)
Ah, OK. Clever. So, charge time depends on power supply and not something inherent in the device! Yes, that makes perfect sense!
> An evil use is to require the > power supply to authenticate to the connected device, in order to sell > power supplies at inflated prices^W^W^W^W^W^Wprotect the consumer.
And, of course, the truth is probably somewhere in between. Thanks! That makes things a lot clearer! I will have to get a bright light and loupe and peer *in* the end of the plug. There should be a conductive surface there in addition to the pin. (and, *probing* would obviously be something done with care lest "something" get shorted to the pin!)
Hi Jasen,

On 11/15/2013 9:41 PM, Jasen Betts wrote:
> On 2013-11-15, Don Y<This.is@not.Me> wrote: >> They're everywhere! >> >> And, often CRAP! > > Sturgeons law?
Isn't that CARP? :>
>> Any guidelines on selection criteria? > > You mean like current limits and mating cycle counts?
Yeah but most of the issues I've seen have been mechanical related. Hence "CRAP".
>> Any worries about failure modes? > > The cable seems to die first in my experience.
Often lots of fatigue just past the strain relief. But, I have seen the device into which the cable plugs also experience failures -- "jacks" snapping off or developing intermittents as they lose their adhesion to the solder pads. Very annoying on laptops (as they are often a PITA to disassemble without breaking ots of little plastic things!)
>> Do the "inverse" variety (now popular on laptops, LCD's, etc.) offer >> any special advantages over the traditional style? > > AFAICT three contacts.
Yes, I realized that from Matt's post just now. Thanks. Previously, anything with more than 2 contacts had been obvious in a plastic molded plug. IBM & Dell made several laptops like this. I'd always assumed the extra pin was another supply -- much like it is on many external (USB) disk enclosures. I will have to make a point of gutting one next time I come across a "spare".
"Don Y"

>>> Any worries about failure modes?
** The most annoying and expensive ( for owners) to fix falure is when sockets develop cracked joints on the PCB. Single sided boards are the main culprits, as there is so little strength in the copper foil to resist movement. Some makers try to wedge socket inlets into a hole in the case - that helps a bit. But far better is to use sockets that fasten to the case with a nut OR a pair of bolts to the case or PCB. If I see a keyboard instrument with a broken DC inlet - I usually fit a whole new connector that fastens to the case. 2 or 4 pins "CB mic" connectors with locking rings are ideal .... Phil
On 15.11.13 18:11, hamilton wrote:
> On 11/15/2013 3:04 AM, Paul E Bennett wrote: >> Cannon XLR connector > > Digikey has these at $20 a pair ( one male/one female ) !!!!! > > Just for power ?!?! >
If you're not happy with the price, have a look at Lemo <http://www.lemo.com/en>. -- -T.
On Sat, 16 Nov 2013 14:58:22 +1100, "Phil Allison" <phil_a@tpg.com.au> wrote:

> >"John Larkin" >"Phil Allison" >> >>>"Phil Hobbs is insanely autistic " >> >> I know Phil, > >** No you don't. > > >> and he's not. > > >** Impossible for someone as fucked in the head as you to even tell. > > Cos the exact same comment applies 100% to you. > > Asshole. > > >.... Phil > >
On second thought, you and Sloman really ought to get to know one another better. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
In article <beo7a0FkeakU1@mid.individual.net>, Phil Allison
<phil_a@tpg.com.au> wrote:

> "Joe Gwinn" > > > >> ** The term "barrel connector" must be an Americanism - cos I have never > >> heard it before. > >> > >> It alludes to resemblance of the male connector to a gun barrel - right > >> ? > > > > Nahh. Whiskey barrel. > > **See: > > http://www.vetco.net/catalog/images/PH-250LB-1.jpg > > Nahh.
Doesn't this connector seem confused about its gender? Joe Gwinn
On Fri, 15 Nov 2013 21:49:52 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 11/15/2013 9:41 PM, Phil Allison wrote: >> "Phil Hobbs is insanely autistic" >> >> >> ** Get cancer and die - you know nothing, fucking MORON >> >> >> >> >>>> "Phil Hobbs is insanely autistic" >>>>> >>>>> Phil Allison >>>>>> "Don Y" >>>>>> >>>>>>> They're everywhere! >>>>>>> >>>>>>> And, often CRAP! >>>>>>> >>>>>>> Any guidelines on selection criteria? Any worries about failure modes? >>>>>>> >>>>>>> Do the "inverse" variety (now popular on laptops, LCD's, etc.) offer >>>>>>> any special advantages over the traditional style? >>>>>> >>>>>> >>>>>> ** The term "barrel connector" must be an Americanism - cos I have >>>>>> never >>>>>> heard it before. >>>>>> >>>>>> It alludes to resemblance of the male connector to a gun barrel - >>>>>> right ?
It would be the female part that sorta resembles a gun barrel but I doubt that's where it got its name, though.
>>>>>> How pathetic. >>>>> >>>>> "Barrel connector" historically refers to M-M or F-F RF coax connectors.
It also refers to the common DC power connector. e.g. <http://www.digikey.com/product-detail/en/S760/SC1052-ND/109419>
>>>> ** Does it - news to me. >>>> >>>> >>>>> Applying it to coaxial power connectors ... >>>> >>>> >>>> ** Has probably got nothing to do with the above at all. >>>> >>>> >>>>> is a perfectly ordinary bit of technical illiteracy of the sort we all >>>>> know and love, probably coming from some ESL type in the Far East. >>>> >>>> ** You just made that up. >>>> >>>> >>>>> IOW you made that up. >>>> >>>> ** No, you made shit up. >>>> >>>> I asked a simple question. >>>> >>>> BTW: >>>> >>>> Fuck off - you vile, autistic pile of septic shit. >>>> >>>> >>>> >>>> .... Phil >>>> >>>> >>> >>> Enjoy! >>> >>> Cheers >>> >>> Phil Hobbs >>> > >Well, you seem to think that I'm an American, based on your poorly-aimed >insults. Guess again.
I'm amazed to see you as the target of Phyllis' psychotic rage.
On 11/16/2013 8:27 AM, John Larkin wrote:
> On Sat, 16 Nov 2013 14:58:22 +1100, "Phil Allison" <phil_a@tpg.com.au> wrote: > >> >> "John Larkin" >> "Phil Allison" >>> >>>> "Phil Hobbs is insanely autistic" >>> >>> I know Phil, >> >> ** No you don't. >> >> >>> and he's not. >> >> >> ** Impossible for someone as fucked in the head as you to even tell. >> >> Cos the exact same comment applies 100% to you. >> >> Asshole. >> >> >> .... Phil >>
Phil you seem to be free of all medication at this point and now have demons running around in your mind. It doesn't seem like it is working well. Please use some new abusive terms for me, your same old line is, well, get old. Thanks, Mike