Post by thread:[EE] DC Power jacks

Here am I, trying to figure out what the deal is with DC power jacks. What do PICListers use most commonly? My experience indicates that there are relatively few commonly used DC jack types, mostly the ones included with common universal adaptors. There's the "standard" DC barrel which seems to be the most common (~5mm outer diameter), EIAJ (yellow tip) plugs, the miniature version of the standard jack (I've seen this in virtually every USB hub and USB external HDD), and a few others. However, when I actually go to buy some, there seem to be 30 or 40 different types and sizes. Even Radio Shack seems to have come up with 21 different types. The type I'm most concerned with is the common DC jack, with an outer diameter of around 5mm. Note that I say "around", because there seem to be several variants with slightly different sizes that are common. I've seen 4.5mm, 5.0mm, 5.5mm, etc, with different combinations of inner diameters. How do I navigate through all this mess? What sizes should I use to try to be compatible with the largest number of devices and adapters, both for plugs and for sockets? What are the consequences of slightly differing connectors? And why in the hell is there no standard for all this that people actually use? I have quite a collection of adapters of different voltages which I use for several projects. Incidentally, the reason why I'm asking about this is because I'm about to build a clone of a certain device that was just fried by an adapter that claimed to output 12V but instead put out 18V. -- Hector Martin (spam_OUThectorTakeThisOuTmarcansoft.com) Public Key: http://www.marcansoft.com/marcan.asc

> Here am I, trying to figure out what the deal is with DC > power jacks. What do PICListers use most commonly? 2.5 mm inner pin. slightly more robuust than the 2.1 inner pin. I prefer center pin = positive because that reminds me of coax cable (ground is outer). > However, when I actually go to buy some, there seem to be 30 > or 40 different types and sizes. Even Radio Shack seems to > have come up with 21 different types. Check what is supplied when you buy a universal wall-wart, here I get some 10 plugs with it. > Incidentally, the reason > why I'm asking about this is because I'm about to build a > clone of a certain device that was just fried by an adapter > that claimed to output 12V but instead put out 18V. For an unregulated adapter that is quite normal. When I put a power connector on anything I make sure that is accepts a wide range of voltage, and survives inverse polarity. Most gadgets I see seem to be designed likewise, but I recently got a USB hub that uses a stabilised 5V DC wall-wart. That gives me the creeps. Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: http://www.voti.nl consultancy, development, PICmicro products docent Hogeschool van Utrecht: http://www.voti.nl/hvu

> Here am I, trying to figure out what the deal is with DC power jacks. > What do PICListers use most commonly? > > However, when I actually go to buy some, there seem to be 30 > or 40 different types and sizes. Even Radio Shack seems to > have come up with > 21 different types. > > How do I navigate through all this mess? What sizes should I > use to try to be compatible with the largest number of > devices and adapters, both for plugs and for sockets? What > are the consequences of slightly differing connectors? And > why in the hell is there no standard for all this that people > actually use? ...and then there are the short / long barrel varieties too. I believe the methodology is: 1. Hang part list on wall. 2. Throw dart. 3. Flip coin to set polarity. Or 1. What's surplus today? As you say, most seem to use a 5mm OD, not sure on ID, and negative to exterior. The only solution for maximum compatibility is to do what those replacement transformers do, and supply 6 or 7 adapter tips. They let you reverse polarity too. (Remember when power conector were often 3.5mm, and you had those 'star' connectors with the bonus 9v plug?) See what those transformers use, they should cover most of it. I know Sony like to invent a new plug every few years. I've to a bunch of plugs / sockets with allicator clips on the end. Comes in handy with oddball stuff, like people using RCA as a power connector. It would be nice if the sizes actually meant something, like different voltages. Tony

> What sizes should I use to try to be compatible with the largest > number of devices and adapters, both for plugs and for sockets? I think the most common is the 2.1mm http://www.powersuppliesonline.co.uk/public/ranges/images/27/JR94C.jpg with its corresponding PCB or panel socket Lower profile devices that haven't the physical room for a 2.1mm might use a 1.3mm On one of my products I have a 2.1mm panel socket as the power connector and a 2.5mm socket as a switched outlet. That way, although they look similar, they can't be plugged into incorrectly > And why in the hell is there no standard for all this that people > actually use ? No standard for polarity either. Probably there are commercial reasons. Your average Joe Blow doesn't know that they could use a cheap wall wart instead of the expensive 'recommendation' For example my nephew was about to spend a small fortune on battery eliminators for his guitar effects pedals. "Whoa there", I says, and showed him how you could do the whole lot for $10 I've made him an LM317-based variable voltage outlet for the cigarette lighter socket in his car so he can pretty much power any small video or audio appliance. I had to include a bagfull of adaptors (with a common connector type on one end - they come supplied with some transformers) and they fit most devices. Not an iPod of course, you have to spend up specially for one of those. When I was in an appliance store last week, I was hovering around the iPod/mp3 player cabinet and thought some of the prices were quite reasonable. Then I realised I was looking at accessories in boxes with iPods on, not actual iPods. They didn't seem so cheap after that. A bit of a rip-off really for what they were (designer covers, straps etc)

I would say that the 2.1 x 5.5 mm (Radio Shack type "M" tip) with positive center is as close to a standard as there is , with 2.5x5.5mm (Radio Shack type "N" tip) a close second and 1.3x3.5mm an equally close third. The 1.3x3.5mm seems to be THE choice when real estate is an issue. --- cheers ... 73 de brian riley, n1bq , underhill center, vermont <http://web.mac.com/brianbr/> Tech Blog <http://www.wulfden.org/TheShoppe.shtml> Home of the K107 Serial LCD Controller Kit FT817 Power Conditioner Kit Tab Robot Laser Tag Kit MSP430 Chips and Connectors Propeller Robot Controller SX48 "Tech Board" Kit On Sep 7, 2007, at 4:07 AM, Hector Martin wrote: {Quote hidden}> Here am I, trying to figure out what the deal is with DC power jacks. > What do PICListers use most commonly? > > My experience indicates that there are relatively few commonly used DC > jack types, mostly the ones included with common universal adaptors. > There's the "standard" DC barrel which seems to be the most common > (~5mm > outer diameter), EIAJ (yellow tip) plugs, the miniature version of the > standard jack (I've seen this in virtually every USB hub and USB > external HDD), and a few others. > > However, when I actually go to buy some, there seem to be 30 or 40 > different types and sizes. Even Radio Shack seems to have come up with > 21 different types. > > The type I'm most concerned with is the common DC jack, with an outer > diameter of around 5mm. Note that I say "around", because there > seem to > be several variants with slightly different sizes that are common. > I've > seen 4.5mm, 5.0mm, 5.5mm, etc, with different combinations of inner > diameters. > > How do I navigate through all this mess? What sizes should I use to > try > to be compatible with the largest number of devices and adapters, both > for plugs and for sockets? What are the consequences of slightly > differing connectors? And why in the hell is there no standard for all > this that people actually use? > > I have quite a collection of adapters of different voltages which I > use > for several projects. Incidentally, the reason why I'm asking about > this > is because I'm about to build a clone of a certain device that was > just > fried by an adapter that claimed to output 12V but instead put out > 18V. > > > -- > Hector Martin (.....hectorKILLspam@spam@marcansoft.com) > Public Key: http://www.marcansoft.com/marcan.asc > > --

Tony Smith wrote: > ...and then there are the short / long barrel varieties too. Of course. > 3. Flip coin to set polarity. Sadly, inside positive makes sense from a coaxial perspective and seems to be the most common, but a standard PCB mount DC socket has a NC contact on the barrel contact which makes it impossible to use that functionality to switch between internal and external power when you can't switch ground instead of positive! I had this dilemma once with a dual USB/External powered device. Ended up using a switch. > (Remember when power conector were often 3.5mm, and > you had those 'star' connectors with the bonus 9v plug?) Yes, they made nice little sparks when plugged/unplugged since they shorted out in the process! At least they were standardized though. > See what those transformers use, they should cover most of it. I know Sony > like to invent a new plug every few years. All of the ones I'm concerned with use the 5mm OD. I just want (for my current project) a panel mount socket that will accept most plugs of the 5mm variety. > I've to a bunch of plugs / sockets with allicator clips on the end. Comes > in handy with oddball stuff, like people using RCA as a power connector. It > would be nice if the sizes actually meant something, like different > voltages. That's the point of EIAJ plugs (the yellow tip ones). Size means voltage IIRC. Few people use them though. -- Hector Martin (hectorKILLspammarcansoft.com) Public Key: http://www.marcansoft.com/marcan.asc

wouter van ooijen wrote: > For an unregulated adapter that is quite normal. When I put a power > connector on anything I make sure that is accepts a wide range of > voltage, and survives inverse polarity. Most gadgets I see seem to be > designed likewise, but I recently got a USB hub that uses a stabilised > 5V DC wall-wart. That gives me the creeps. I have a rather large number of recent devices that all use regulated 5V switching wall warts. - FPGA board (Digilent Spartan-3E Starter Kit) - PDA (Sharp Zaurus, all models IIRC) - Nintendo DS - 2.5" USB hard drives (pretty much every model) - some small USB hubs - La Fonera (That small, cheap, somewhat poorly designed locked-in router that people like me like to hack and use as a general purpose access point/router) All use 5V stabilized power. The wall warts are convenient for PIC projects though :) > > Wouter van Ooijen -- Hector Martin (.....hectorKILLspam.....marcansoft.com) Public Key: http://www.marcansoft.com/marcan.asc

On Fri, 2007-09-07 at 11:35 -0400, Hector Martin wrote: {Quote hidden}> wouter van ooijen wrote: > > For an unregulated adapter that is quite normal. When I put a power > > connector on anything I make sure that is accepts a wide range of > > voltage, and survives inverse polarity. Most gadgets I see seem to be > > designed likewise, but I recently got a USB hub that uses a stabilised > > 5V DC wall-wart. That gives me the creeps. > > I have a rather large number of recent devices that all use regulated 5V > switching wall warts. > > - FPGA board (Digilent Spartan-3E Starter Kit) > - PDA (Sharp Zaurus, all models IIRC) > - Nintendo DS > - 2.5" USB hard drives (pretty much every model) > - some small USB hubs > - La Fonera (That small, cheap, somewhat poorly designed locked-in > router that people like me like to hack and use as a general purpose > access point/router) > > All use 5V stabilized power. The wall warts are convenient for PIC > projects though :) Which has been great for the surplus market. A local electronics store has sold 5V 1A regulated switching wall warts for $2/each for quite a while now, I've got tons... :) TTYL

Hi- I have used the "RCA" type audio connectors with mixed sucess. It was convienent because I had a lot of both plugs and jacks. There are downsides that include: There is a possiblity of shorting the tip (which protrudes) to the ring when the wall wart is left plugged in and the connector is left lying on the bench with various bits of metal around....... Some people might confuse the purpose of the jack as it typically is used as a "line" input/output to audio which might provide some surprises to those not clued in. The connector is not the most robust method of interconnection and there is a chance with wear that it will fail to make good contact. All in all, if you want to standarize with a power connector, I might suggest looking at the polarized Molex type connectors with pins and jack pins. It might be a tad bit more work crimping on the pins and plugs, but each pin is rated at an amp, they can reasonably isolate the plugs, female (sourcing power) from accidental shorting. There are a variety of them available, one common example is the 4 connector version that are used for disk drives in PCs. Note that you can get both PC mount versions and crimps for both sides. Also, they seem to mechanically connect fairly well with each other and not come apart unexpectedly. One downside that I've seen with these is that the housing tend to darken and more importantly harden and turn brittle when to much current passes through the pins and the temperature of the junction rises. The other is that they are rather big. Other than that, they seem to work pretty well. Cheers, Rich S. {Quote hidden}> > I would say that the 2.1 x 5.5 mm (Radio Shack type "M" tip) with > positive center is as close to a standard as there is , with > 2.5x5.5mm (Radio Shack type "N" tip) a close second and 1.3x3.5mm an > equally close third. > > The 1.3x3.5mm seems to be THE choice when real estate is an issue. > > --- > cheers ... 73 de brian riley, n1bq , underhill center, vermont > <http://web.mac.com/brianbr/> Tech Blog > <http://www.wulfden.org/TheShoppe.shtml> > Home of the > K107 Serial LCD Controller Kit FT817 Power Conditioner Kit > Tab Robot Laser Tag Kit MSP430 Chips and Connectors > Propeller Robot Controller SX48 "Tech Board" Kit > > > > On Sep 7, 2007, at 4:07 AM, Hector Martin wrote: > > > Here am I, trying to figure out what the deal is with DC power jacks. > > What do PICListers use most commonly? > > > > My experience indicates that there are relatively few commonly used DC > > jack types, mostly the ones included with common universal adaptors. > > There's the "standard" DC barrel which seems to be the most common > > (~5mm > > outer diameter), EIAJ (yellow tip) plugs, the miniature version of the > > standard jack (I've seen this in virtually every USB hub and USB > > external HDD), and a few others. > > > > However, when I actually go to buy some, there seem to be 30 or 40 > > different types and sizes. Even Radio Shack seems to have come up with > > 21 different types. > > > > The type I'm most concerned with is the common DC jack, with an outer > > diameter of around 5mm. Note that I say "around", because there > > seem to > > be several variants with slightly different sizes that are common. > > I've > > seen 4.5mm, 5.0mm, 5.5mm, etc, with different combinations of inner > > diameters. > > > > How do I navigate through all this mess? What sizes should I use to > > try > > to be compatible with the largest number of devices and adapters, both > > for plugs and for sockets? What are the consequences of slightly > > differing connectors? And why in the hell is there no standard for all > > this that people actually use? > > > > I have quite a collection of adapters of different voltages which I > > use > > for several projects. Incidentally, the reason why I'm asking about > > this > > is because I'm about to build a clone of a certain device that was > > just > > fried by an adapter that claimed to output 12V but instead put out > > 18V. > > > > > > -- > > Hector Martin (hectorspam_OUTmarcansoft.com) > > Public Key: http://www.marcansoft.com/marcan.asc > > > > --

Hector, On Fri, 07 Sep 2007 11:31:25 -0400, Hector Martin wrote: >... > That's the point of EIAJ plugs (the yellow tip ones). Size means voltage > IIRC. Few people use them though. However, I have a Sony in-car adaptor which has such a plug, but which is switchable between 4.5 and 6V, so that clobbers that standard! :-) Incidentally, I concur with an earlier post which said that 2.5 x 5.5mm and 2.1 x 5.5mm are the most common, but I have a little box of 16 plugs in various sizes to get round awkward situations, and even then there are some things that are so non-standard that I can't find anything to fit. For example a Smith Corona labeller, which has 6 AA batteries inside that run down rather fast, and to get round an obvious design flaw they supply a little plastic "battery saver" plug to go into the DC socket that operates the in-socket switch to disconnect the batteries "when not in use"! I would use an external PSU but I can't find a plug to fit - seems to be about 6.3 x 2.5mm and I haven't seen those anywhere. Cheers, Howard Winter St.Albans, England