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Connectors: A History of Their Technology?
dpbsmith asks: "It seems like a simple engineering problem--construct a device for easily and safely connecting several dozen wires at the same time--but the variety and creativity in their design over the years has been amazing, and, clearly there have been trends, fashions, and styles. In the fifties and sixties, virtually all connectors were roughly similar to the D-Sub design used for RS-232. A stiff, straight pin engaged a springy socket that contacted and bore against it on all sides. There were minor variations in shape and placement; the Amphenol Blue Ribbons (think Centronics), the connectors into which circuit boards engaged, but they were all variations on a theme. I was absolutely astounded the first time I saw a modular RJ-11 connector. Cheap, effective, and utterly unlike anything I'd ever seen before. Who invented these? Western Electric? Recently, we have the USB connector and the Firewire connector, obviously members of the same family (and a cheap-and-cheesy-seeming family it seems); on the other hand, my telephone and my digital camera have connectors that are very small and snap in with a positive lock that must be released with a squeeze, obviously yet another fundamentally different design. What do people know about the design, history, and engineering behind connectors over the years? Is it all hidden away, trade secrets of the connector companies, or is their a story that can be told?"
If we're talking about connecters, we should take time to ponder the mystery of BNC connecters, their origins, and what the hell BNC stands for anyways!
"I hope they legalize drugs so you hurry up and fucking die." Charles Bronson (the band, not the man)
You can find more info in the Cable FAQ through Google.
Ben Brown obviously likes big connectors http://www.benbrown.com/switch/
One of the coolest things about connectors is that the Atari 2600, C64 and Sega Genesis all had the same 9-pin connector. You can hook a Genesis pad up to your 2600 and it works well (B is the only button that works, along with the D-pad). There's even a hack for making the Genesis pad work with the two-button 7800 -- sadly I can't find the link atm. Coolest thing I've seen recently is a converter that lets you use PlayStation dual-analog controllers on the Atari 5200. I believe I saw something about it here.
Dude, I think I can see my house from here.
They're OK as long as the manufacturers build them with keys. Without keys they are a veritable PITA.
I was six when i first heard of the term "male" and "female" connectors. Even though I keep pestering my dad about
1) which one is male / female, and
2) why they name it something stupid like that
he just kept "umm... ahhh"-ing and never answered.
I was like 17 when it finally dawned on me why they named it that way. ha! then it all made sense.
moral of the story are:
a) who says electrical engineers / connector designers are not perverted?
b) to save yourself trouble, don't talk about male/femail connectors in front of little kids.
My life in the land of the rising sun.
Perhaps they should rename themselves "Packard Dell."
One CPU cycle wasted on digital restrictions management is ONE TOO MANY.
Talking about connectors, one thing that really mades me mad is the amount of power supply adapters we have to have these days. My office floor is littered with them, for net routers, printer, laptops, displays, mobiles etc. etc. Why can't we have two circuits? And for that matter, why are electric plugs so big. In the UK the are enormous. Many things these days only take a tiny bit of power - can't we have smaller electrical plugs? On my travels it seems that in the rest of the world electrical plugs are pretty big too. Is there anywhere with little dainty ones and without huge power adapters? Japan perhaps?
Miniaturizing transformers is really expensive - having those devices come with smaller transformer would noticably add to the price of the device.
To make laws that man cannot, and will not obey, serves to bring all law into contempt.
--E.C. Stanton
Yeah, the pornographic nature of electrical connectors is pretty strange and amusing. One wonder how the bluenoses let this happen!
Another example: joystick. These were originally invented for high-accelleration aircraft, where the pilot was subjected to G-forces that prevented him (it was always a him, of course) from lifting his hands out of his lap. So they invented a flight control that consisted of a simple stick between the pilots legs. The masturbation metaphor was unavoidable, but where were the censors when all this was a happening? This was the 1950s and America was overrun with Guadians of Virtue. I guess the only answer is that GoVs are just plain dense!
It might be easier if we switched from 60Hz to something around 20kHz.
You want to overclock the power lines?
To make laws that man cannot, and will not obey, serves to bring all law into contempt.
--E.C. Stanton
I've spent many unhappy hours trying to get the IDE cables from the interfaces on the motherboard to the disk 18.1 inches away :(
Personally, my favorite connector has to be the Camlok E-series power connector. There is just something "interesting" about a connector that is rated for 400+ amps of current flow. And just TRY to break one or pull it off the wire...
For multipin, I would have to say that the old IBM Latchback connectors are tops on my list. 240+ pins, all designed to mate at the same time, all gold plated, and designed for low level signals (unamplified audio for example). Single cam based latching mechanism, keyed, and easily maintainable.
Of course, if you have never work in a concert hall, you probably will NEVER see any of these connectors in real life....
Ron Gage - Westland, MI
The best connectors, bar none, are the USB/FireWire connectors. Small and cheap but not flimsy, easy to insert and remove (little pressure), but good retention, nearly impossible to break under normal circumstances, capable of carrying power, no stupid retention clip, compact but not tiny...
In north america, it seems that all computer power cords are standardized. I don't mean the standard electrical plug. But the "other" end of the cord. Whether it plugs into a calculator, adding machine, comptuer, monitor, or some other types of equipment.
It has a standard sized six sided shape with three holes for metal prongs to fit into.
Perhaps, you've seen a cord with a connector that is the opposite gender of these. It might, for example, but a cord comming out of a monitor with a connector that accepts a standard computer power cord.
This cord has metal prongs (male?) but a sheath around the prongs into which the bulk of the plug from the other end fits (femals?).
If you know the kind of connector I'm talking about, then why can't electrical power plugs work like this?
At present, electrical plugs have metal prongs that can be touched with your fingers while the plug is partially inserted into the electrical outlet. What if there were a plastic "fence" around the group of prongs so that it was impossible to touch the prongs while it is being inserted into an outlet? The outlet would have to have the "cutout" for this plastic fence to fit into.
Anyone who has plugged an Apple monitor's electrical cord into the Mac so that the Mac controls the flow of power to the monitor knows what I'm talking about here. It is impossible to touch the prongs while you're inserting the plug into the socket.
The price of freedom is eternal litigation.
With the recent 802.11b Wifi craze I'm surprised anyone hasn't mentioned the RP-TNC connectors that appear at the back of the popular Linksys WAP11.
They have proved very hard to find, and expensive to order. The connector or adapter cable often prove to be the most expensive part of a homebrew antenna!
Does anyone have any antenna / RF cable tips or know of stores in the SF bay area?
I love connectors. I love sticking wires into a DB25 to make my TI82 talk to my PC. I love crimping RJ45's (nothing beats that satisfying perfect crimp). I love squishing down a 50 pin IDC with a pair of visegrips (or a vise, if I'm lucky :)). Maybe it sounds trivial, but there's just something about connectors and interfaces that makes me smile. Yes, I am insane.
Might as well plug my favorite DC power connectors, Andersen Powerpoles Modular, color-coded, genderless, super-easy to assemble, safe, positive click on connect, etc. Emergency services are quickly adopting them as the standard for all 13.8v (12v nominal) gear for their setups. Perhaps a few cents more than the cheap barrel connectors or Molexes, but they're definitely worth it. I've driven over 12-year-old Powerpole connectors and they're none the worse for wear.
(no connection between me and andersen besides happy customer status, btw.)
Hey Taco! Looks like you're using the "infinite monkeys and typewriters" scheme to generate Ask Slashdots again...
Fahnestock made the clip.
And it was good.
--Blair
"Bring back the B-Cell."
I'm always impressed by the connectors for peripherals (generally controllers) on modern video-game consoles. Consider, if you will, the humble playstation connector:
If only connectors for "grownups" were designed this way.
## W.Finlay McWalter ## http://www.mcwalter.org ##
And male panel connectors are called jacks, too.
Male/Female refers to the contact type.
Plug/Jack refers to movable/fixed. The more movable connector (eg, on the end of a cable) is a plug, and the less movable connector (eg, on a panel) is a jack. This is covered in the ANSI standard for reference designators.
Can anyone think of a crappier design than SCART??!
The USB mechanical spec calls out that the USB logo be molded on one side of the cable in such a way that you can feel it and the other side be smooth. The logo is specified to go up.
:-(
And all was good.
Until manufacturers could save $0.02 by putting their jacks on upside down or sideways. Now you have a bunch of nicely polarized cables that you can orient blindly in the mess of cables, but have no idea which way the jack is oriented.
(Yes, I have an upside down computer from a vendor that knows better and screwed me for $0.02.)
Yes I'm sure there's a Bulgarian Nympho Club, but thats beside the point.
I just checked on google. No Bulgarian Nympho Club. At least not on the web. Damn. I just posted to tell everyone to not get their priceline tickets to Bulgaria just yet.
Medical Ultrasound systems have a unique connector problem. An ultrasound probe has to connect to the ultrasound machine, but there are a huge number of signals that must get transmitted. The traditional ultrasound probe has a connector that looks like a huge 2" by 5" RS-232 plug with up to 256 pins (more in some cases).
To prevent constant pin breakage and bending, most ultrasound machines have special guides on the ports (jacks) so that the plug can only be inserted at a precise angle. But it still happens. When you've paid up to $50,000 for an infant cardiac transesophogeal multiplanar probe and you break a half-cent pin, you tend utter words that should not be uttered near an infant needing such a diagnostic examination.
Acuson invented a new type of connector for their Sequoia line of ultrasound systems. The "MP" connector is a flat plate that rests snuggly against another flat plate in the port, held secure by a quick release knob. Imagine a very large inkjet cartridge connector. Unlike an inkjet connector, they're very rugged, and spec'ed out a heck of lot tighter. No more broken pins! And they're a lot easier to attach and detach than the old style.
A Government Is a Body of People, Usually Notably Ungoverned
The crufty among us will remember the ultimate minimalist connector. The original ethernet (thick wire) used a large coax cable as the backbone. You connected to it by drilling a tiny hole and inserting your tap into the cable in such a way that it made contact to the core and shield without shorting anything and wiping out the whole network.
:-)
It really made 50ohm BNC look good when it came out.
No, actually at higher frequencies, the impedance of the line increases dramatically (current is only flowing on the outer surface, rather than through the entire cross-section as you would see with DC).
RJ-45 is a connector, not a cable. RJ-45 can be connected to a number of different cables, category 5 is the most common for PC networks. The 4-wire cable used for telephones has nothing whatsoever to do with the RJ-11 connector. God save us all from cluebie linux dweebos. A little bit of knowledge is a dangerous thing.
Shutting down free speech with violence isn't fighting fascism. It IS fascism!
Look in your basement, at where your washer and dryer are plugged in. Very different.
What we call folk wisdom is often no more than a kind of expedient stupidity.-Edward Abbey
Gotta love them - at first they look like a 25-pin serial but on closer inspection they've got 3 little bnc-style connecters and a bunch of control pins :)
Years ago, I saw a connector that used small metal brushes instead of pins and sockets. Each connector had a set of brushes, which would mate with the brushes in the other connector.
Mea navis aericumbens anguillis abundat
The 400Hz power is still using bigger wires for the current. I imagine the total amount of copper for doing 400Hz distribution is much higher, which is why it has all but disappeared from the data center and is only relegated to airplane APU's.
This has to do with an air connector.
,the guy also happened to be the biggest jerk I ever worked with- then or since.
A few years back I was serving on active duty in the US Navy. The ship I was on was in drydock for overhaul at the time. We were performing asbetos ripout on a large space so you had to suit up in a tyvek overall suit and breathe via a mask connected to an air supply via a hose. The connecot on the hose was called a quick-disconnect fitting. If you have ever used pressurized air tools you know what I'm talking about. To connect the hose you simply push a hale fitting into the female fitting. To disconnect you just have to lift a small spring-loaded collar and pull the fittings apart.
One night I was standing the6PM-Midnigh watch. On that particular watch you have to go to the command center (EOS -Enclosed Operating Station) and get your logs signed by the Officer on duty. This particular night when I went to go get my logs signed around 1150 PM. The Office asked me to stand in the EOS and wait for him to do a quick inspection of the engineering spaces.
As I waited all the other watchstanders gradually appeared at the EOS to get their logs signed. Naturall, with about ten people milling about in a small space a lot of conversations started up.
Normally most of the watchstanders in the EOS wear headphones to hear the communications in the engineering spaces. Since so many were talking aloud thay all had hung up their headphones with their earpieces pointed outward just in case someone called in.
Time really flew by and before we knew it the time was 12:30 AM and we hadn't heard from the watchofficer. One of the watchstanders picked up a phone and paged him on the loadspeaker through the engineering spaces. Nothing. No reply for almost five minutes. Worried, a coulple of watchstaders began to leave the EOS to look for him.
Suddenly we someone paged me personally via the phones. I picked up a handset to answer the call. I responded and the Officer said," Petty Officer, I'm calling because something rather embarrasing has happened and I know I can trust you to keep this quiet. I went down to the lower level to inspect the asbetos ripout area and hook up to this air thingy and can't seem to get it to disconnect."
The first thing that flashed through my head was that everone in the entire engineering room had just heard his "secret" because of the headphones hanging. Second, this guy has just spent 45 minuted trying to figure out how to disconnect a quick-disconnect fitting. I hit the floor laughing. Master's Degree in Engineering from an Ivy League School, several years of the best technical schooling the US Navy has to offer and this guy can't figure out a quick disconnect fitting.
Needless to say, by the time myself and everyone else recovered we managed to talk him through getting it disconnnected. He never did live that one down. Every newby watchstander would give him a smirk and a knowing look when they had to deal with him face-to-face. BTW
"God fights on the side with the best artillery." - Napoleon, Marshal of France - speaking truth to power
You will never see them on consumer grade electronics equipment, but they are widely used on military electronics equipment and commercial equipment that has to survive in a hostile environment. They are weatherproof cylindrical multi-pin connectors with a twist-lock collar. They come in a wide variety of sizes and configurations.
Mea navis aericumbens anguillis abundat
The vast majority of the electrical connectors you see are either male of female. They're all built just to mate with its complement, which raises parts storage issues as well as restricts how things can plug into eachother. I got a hold of genderless-mating modular connectors that can snap together in many configurations, and have no concept of 'male' or 'female'. They're apparently made by Anderson Power Products. I have a few pictures of their smaller connectors here. Connectors like these would be GREAT for daisy chaining DC power sources and/or building quick-disconnect battery charging harness, since their design maintains polarity regardless of the "direction" of the connector (supply to supply, battery to battery, battery to supply, etc)
The skin effect is only relevant with frequencies of the order of MHz (or higher).
This would be a very bad idea. As you may know, ferromagnetic materials present what is called the hysteresis cycle. If you don't know what this is, Google for it.
In short, what it means is that magnetic domains inside the material retain their orientation even after an external magnetic field has been switched off. This happens because disaligning the domains would require energy.
Transformers use ferromagnetic cores, so essentially the domains inside the core change orientation 60 times per second in 60 Hz systems. Doing so dissipates heat due to the fact that the domains "resist" being realigned in an opposite direction.
If you increase the frequency by a factor f, you end up increasing hysteresis losses by f as well, and this is a *very* big deal. In short, transformers would be much less efficient.
Then, you'll need some type of converter (hence increased losses) at the production sites. Remember, most of electricity produced in the US is from a tubine coupled with an alternator. It's very easy to have the axle of a turbo-alternator to go faster than the resulting electrical phase, but much difficultier to do the opposite.
In a common turbo-alternator, IIRC, n=60*f/p, where n is the rotational speed (RPM), and p is the number of pair of poles on the rotor, and 60 is to have the speed in RPM rather than RPS (or Hz). So if you want some insane number for f (like 20kHz), your standard run-of-the-mill turbine (2 pair of poles, which normally runs at 1800RPM) will need to resist to 600000RPM. Of course, if you want it to actually hold together, you'll need to make it run slower (I remind you that a Dremel is ~30000RPM max), so let's say you choose 10000RPM (which is still way higher than current equipments). This means you'll need 120 pairs of poles on the rotor, which is a lot. If you need to make it spin at 10000RPM, each one of your poles will need to be really small (or you have a very small radius for your alternator, which mean the same thing).
Just for comparison, the biggest turbo-alternator I know of (doesn't mean there aren't some bigger ones) are for the Three-Gorges dam in China. Something like 20m radius (60ft). Of course it's not supposed to turn at even 100RPM, much probably less.
So having your turbos making 20kHz AC is not very possible. The other solution would be to have some kind of converter between the production and the use. Problem is, each converter (frequency) or transformer (voltage) will have some losses, because of the current running through it, and because of other reasons as well (inductance, magnetic losses, etc.). One of the things electricity producers and distributers hate the most are losses: they don't get money for that electricity, which must be produced anyway. And usually, the losses are estimated to a tenth or a hundredth of a percent before the construction of a power plant. So I don't see the change to 20kHz as really feasible (not to mention the huge installed base and the potential skin effect problems as others have already pointed out).
RE 1/4 audio - this was the standard - the 1/8th is the "Mini" - gos back to the days of manual switchboards - yep, 1/4" audio plugs
BTW properly done line level audio is 600 ohms impedience all through the chain - and is a relic of the phone company - as is "Line Level" - as in telephone line
-- 73 de KG2V For the Children - RKBA! "You are what you do when it counts" - the Masso
Most I'm aware are arranged vaguely like a computer's serial port connector, except that the pins are slightly further apart, and each pin is surrounded by a cylindrical plastic casing (the pin itself is recessed a bit below the end of the cylinder). This way the cylindrical plastic pieces align the connector with the socket before the metal pins actually make contact, making it nearly impossible to bend the pins (which is good when you have kids plugging and unplugging them all the time).
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
Ethernet wiring already takes phones into consideration. Standard procedure is to use pins 1,2,3, and 6 of the RJ-45 connector. This was, if a phone (RJ-11) is plugged in, it will make contact with only the usused pins 4 and 5 or hte RJ-45 connector.
There are some Ethernet arrangements that utilize all eight wires, but these are fairly uncommon.
Amazing. I had been told by many people that this was a British Naval Connector. I was once asked this as a trivia question, answered 'British Naval Connector' and was told I was correct!
/var and /usr. No one seems to agree. It's very new technology but the truth may already have been lost.
Goes to show you how incorrect info can become official if no one checks. Kind of like the origins of the names of files and directories in Unix, like
=rmortyh
It might be easier if we switched from 60Hz to something around 20kHz.
Not if you are going to send the power any distance. In addition to skin effect, magnetic hysteresis, etc., the wires would become transmitting antennas and send the power out into the sky.
The most efficient transmitting antenna is 1/4 wavelength. Wavelength = speed of light/frequency. At 60 Hz, the wavelength is 300,000km/sec / 60 = 5,000 km. Better keep wire runs under 1,000 km, or break them up with intervening transformers & capacitors that shift the phase. Not too hard. At 20 khz, wavelength = 15 km; wire lengths must be under 4 km, and better under 1km. You could use 20KHz for power distribution in a ship or airplane if you didn't mind custom-building the power supply in every piece of off-the-shelf electronics you used, but you cannot use it in a citywide power system.
And there's a very good reason not to use frequencies between 60 and 20,000: audio bands use those frequencies, so power distributed on them would interfere with telephone and music electronics. (60 Hz is actually a bit high for audio systems with good bass response; I suspect some of the best systems must have a rather expensive notch filter built in.)
So, here is what I know. Not everyone here knows their cables or connectors nor do they need to. Here are some simple things to help you out with.
RJ stands for Regents Jack. RJ11 is your typical 2-6 pair telephone jack. RJ45 is your typical 4-5 pair Ethernet pin jack, also gets used for DS1s.
BNC is a Barrel Node Connector. BNC gets used on test equipment, older coax cable NICs for thin or thicknet. Also DS3 twinax cable interfaces. That screw in on the back of your TV set? F-type.
Tons of pretty pictures;
http://www.cmsa.wmin.ac.uk/~alan/compo
Molex appears to have a nice connector tutorial for you to check out. I need to look this over myself;
http://www.molex.com/training/bce/gstoc.
Get yourself a Molex catalog. Every type of cable connector you can imagine. Go to their products page and browse around.
http://www.molex.com
Do not forget Amp, even though their web presence sucks (or last time I looked)
http://www.ampnetconnect.com/
Random cable interfaces, with some pictures;
http://www.peakaudio.com/CobraNet/Netw
Cable Types for 3Com Products
http://support.3com.com/infodeli/tools/
Unix Serial Port Resources: Sun Serial Port & Cables Pinouts
http://www.stokely.com/unix.serial.port.
IEC has standards, like that power plug on the back of your computer -- an IEC 320 plug.
http://www.iec.org/
Your typical U.S. three prong power plug is an NEMA-5-15P (P for plug), and the receptical is a NEMA-5-15R. Here are some charts with pretty pictures;
http://www.leviton.com/sections/techsu
http://www.quail.com/locator/nema.htm
SCSI connectors, pinouts, and protocols, and some IDE/ATA stuff too;
http://t10.org/
Do not forget about the Fiber Channel and HIPPI;
http://www.t11.org
PCI card interfaces;
http://www.pcisig.com/
EIA/TIA;
http://www.tiaonline.org/
Whoa, I just found this... standards for wiretapping?;
http://www.tiaonline.org/standards
Cisco, always a great place to look and learn. Common LAN interfaces from what I see;
http://www.cisco.com/univercd/cc/td/doc/pro
More Cisco, including V.35 and X.21 pictures;
http://www.cisco.com/univercd/cc/td/do
Arg, I had to repost this because Slashdot says, "Your comment has too few characters per line (currently 26.9)." That sucked and needs to change.
If you have more references, please let the world know. I know stuff, you know stuff. Put your stuff here.
I miss the good old days of DB9 connectors on consoles. I can still today take a Sega Genesis control pad and plug it into an Atari 2600 to play games. Works wonders compared to the old joysticks. This was also the time when many consoles could connect to a TV adapter using one standard wire. (Plugged into the side of the adapter, which screwed into the back of the TV)
Why can't we standardize on one connector for many things? Imagine a connector that has identical ends that plug into identical ports on machines (they fit when you turn them around) that can transfer data two-ways and more power than a firewire connector. Is that so much to ask for?
Remember "Bring 'em on"? *sigh
I'm guessing from this last Ask Slashdot that the section exists solely for the Chinese and other censored citizens who can no longer access google.com ... I propose that we replace the Ask Slashdot submission form with a cgi interface to google, it could act like a proxy. This would solve the problem quite neatly.
A computer without Microsoft is like ice cream without ketchup.
Cut both cables with scissors.
Strip the wires about an inch (with your teeth of course).
Twist the right ones together.
Electrical tape and solder optional.
M@
Krispy Cream is people
Incidentally, you're actually supposed to solder a PL-259 plug to RG-8U coax using a propane torch.
There are other RJ-series connectors other than RJ-11/12 and RJ-45.
..RJ11: Normal (1 pair) home phone jack, having 2, 4 to 6 pins
RJ (Modular Connector Jacks (female), Plugs (male)) types:
RJ12: Has 3 pairs of pins: An RJ-11 using 3 pairs of wires
RJ14: Has 2 pairs of pins: An RJ-11 using 2 pairs of wires
RJ22: Normal (1 pair) hanset jack, having 2 to 4 pins
RJ25: Has 3 pairs of pins.
RJ45: Has 4 pairs of pins. Used with RS232, 10BaseT, EIA568.
RJ48: Has 4 pairs of pins. Four voice circuits, used with T1/E1/ISDN.
Happy Fun Ball is for external use only.
If you insist on this, prove it.
The skin effect is irrelevant at such low frequencies. As a matter of fact, your argument is used by audio equipment salesmen for tricking people into buying new cables and connectors and whatnot.
There is NO WAY a sinusoidal waveform at a few kHz will have a significant impact in signal power. There are plenty of usenet posts on this subject as well if you'd like to confirm my claims.
Anyway, stop trolling.
But I should say that given the high voltages (high for the human body, that is), the plugs must be quite large to guarantee a certain level of mechanical sturdiness. I don't want to have a RJ45-sized 100v plug for fear it may someday break when I plug it in.
Heh. Your telephone already does this:
Off-hook voltage: About 5V DC.
On-hook voltage: About 48V DC.
Ring voltage: About 105V 20Hz AC, pulsed in the familiar cycle.
Okay, so, there's no current behind it.
The reason the voltages are so high is to allow for the voltage drop otherwise caused by the line resistance, if they used lower voltages with higher currents.
And, absolutely, I agree with you. But you couldn't draw 1.8kW (120V @ 15A AC line) through an RJ45 anyway. Try it sometime for amusement.
Fire and Meat. Yummy.
If you multiply the frequency by k, you multiply the derivative by k as well (we're dealing with sinusoidal signals here). Therefore, the voltage induced also ends up being multiplied by k.
For sinusoidal signals you have that: E = 4.44fNF, where:
E: voltage
f: frequency
N: number of turns in your winding
F: magnetic flux (the right symbol would be a phi)
So consider the transformer's primary winding. Suppose you connect it to a 127 V outlet, so E = 127 V (RMS). N is a fixed value, so let's ignore it in our analysis. We have that the larger the frequency, the smaller our flux will have to be. The flux is proportional to the current through the winding, so there you have it.
Disregarding losses, a transformer operating at 400 Hz will only draw 15% of the current of one operating at 60 Hz in order to magnetize its core. Therefore, if you design a transformer for 400 Hz you'll use a thinner wire gauge (among other things). But this will limit its use at 60 Hz as you've witnessed.
Regardless, this doesn't have much to do with my previous point. 400 Hz transformers are much less efficient if you use a ferromagnetic core. You can go around hysteresis losses by using ferrite cores, but your transformer will be larger. And ferrite cores can only be used for small transformers, so there's no way you'd be using them for power transmission. Your claim of higher frequencies being "better for devices" doesn't make sense. What does that even mean? As far as domestic devices are concerned, most of them are DC anyway so we'd end up rectifying the signal, thus rendering frequency irrelevant.
Making XLR to 1/4" adapters. . .
Making RCA to 1/8" adapters. . .
Cursing the need to replace the RCA connectors on half the equipment once a year. . .
Building patch bays from scratch due to cheap ass management. . .
I loved that job. Not the working part. Just making the patch cables. Beautiful, lovely patch cables. Perfect solder, shiny beautiful solder. . .
you know. . .now that I think about it. . maybe it was the lead fumes. . .
Find out about my new childrens book: SS Death Camp Criminal Batallion Go To Monte Carlo For The Massacre
1. Ferrite cores have obvious size limitations and are extremely expensive when compared to iron cores, so you can only build domestic appliances with your idea. Even so, most domestic appliances use DC anyway so why even supply them with high-frequency AC?
2. How do you suggest we transmit power over long distances? Using ferrite transformers at substations? *snicker*
So we'd end up transmitting at 60 Hz and then transforming to 20 kHz and then rectifying? This seems amazingly stupid to me.
I should like to nominate SCART connectors as the crappiest ever. Generally made out of cheap thin metal plates, completely easy to bend & distort. Generally overloaded with a relatively heavy cable loom which the connection friction is incapable bearing. French. Ugly. Stupid. Did I say French?
Don't have kids do you? My newborn loves to unplug things. Since he is not strong enough he pulls the cord and prys the plug off. In the process he will sometimes touch the metal prongs and get zapped.
Fortunately we have been more cautious about keeping and eye on him and eliminating plugged in items within his reach, so he hasn't gotten hurt lately.
One can't "just substitute ferrite cores instead of iron laminate" as you claim, because costs would be prohibitive. Our problem isn't a theoretical limitation. Consider large (MVA scale) transformers and the size of their cores. The efficiency gain you'd get from ferrites isn't all that great because the magnetic coupling that iron gives you is quite larger than what is achievable with ferrites (and this is why we have efficiencies on order of 99% on existing transformers). So despite the smaller hysteresis and foucault losses, the transformer wouldn't be so tiny as to compensate for the ferrite's price.
The "inherent size limitation" I talked about is based on the manufacturing costs. Ferrites are too expensive to be used on anything but small transformers due to their cores' small volume, and iron cores are actually quite excellent for us to consider an alternative. (Notice that I'm referring to large transformers and not to the ones found in consumer devices).
There are also manufacturing problems. For example, you'd have to build your large ferrite core from a bunch of relatively small ferrite blocks, which could be inconvenient as they're extremely fragile. And their fragility will grow with size, rendering construction trickier (or maybe impossible in practice, considering the need to transport the transformer? I don't know.)
No, you just have to maintain a solid common ground and good shielding.
Gamingmuseum.com: Give your 3D accelerator a rest.
He's gotten shocked and still plays with the cords? He'll be riding the short bus to school, sure enough.
Gamingmuseum.com: Give your 3D accelerator a rest.
you're not supposed to put a rubber on the male connecter
:o)
Is that to prevent your computers from spreading viruses to each other?
It had something to do with Adam and Eve.
Give me my freedom, and I'll take care of my own security, thank you.
This is exactly what the switch-mode power supply in your PC does. See How Stuff Works.
--zawada
In Soviet Russia, the Beowulf cluster imagines you!
As an EE student, I know how a switching power supply works, thanks. And actually, they first rectify and then make a pulsed signal at x kHz (where x is NOT a constant value), transform and rectify again, so this is not what I'm saying.
I meant that we'd have to transmit at 60 Hz, somehow transform to 20 kHz to use inside our households and then supply our appliances at this frequency. The appliances themselves would decide on what to do, and this would in general involve yet another transformation step. So we'd have 2 transformation steps instead of 1, which is down right idiotic.
The idea is that even thought switching power supplies use high frequency transformers, (1) the frequency changes drastically depending on the load, so providing a fixed 20 kHz feed is absolutely *useless*; (2) even if the frequency didn't change, different supplies need different frequencies; (3) not every device/machine needs a switching power supply (the higher consuming ones DON'T), so we'd be wasting a lot of energy in this transformation step.
God, it's amazing how much bullshit Slashdot can generate from such any subject. You guys should either go to school (and pay attention) or stop making uninformed "corrections".
Junkyard? Good place for them. Too loose, too tight, or just plain unreliable.
Hands-up if you have had to break out the vice-grips to get a secure enough grip to wrench one of these things from its socket.
I am not an electronics technician. But I have built a dozen or so computers over the years, and upgraded or fixed a couple of dozen more. So my experience is relatively limited. Within that limited experience I have found those stupid connectors to be, by far, the most unreliable element in PC style computers.
Cheap metal hooks are crimped on to the wires before they go into the connector. Friction is supposed to be sufficient for the hooks to hold the wires in place. But it is not sufficient.
Here is a horror story.
I had a buddy, who asked me to give him a lift to the computer store, to pick up his brand new computer. I was a bit jealous, as he bought himself a BIG tower case. It had many external bays. It was mounted on casters. It had hinged side panels to give access to the motherboard. I was a bit jealous, and I was sorry I couldn't afford one like that.
I remained jealous for about two months. But then he asked me to give him another lift back to said store, to have his hard drive replaced. He could have carried it on his lap, on the streetcar, if he hadn't bought a the big case.
Well, the owner of the little mom-and-pop shop replaced it, or assured him it was working, three or four times over the next months.
A couple of days after dropping the computer off, I pay a visit to this shop to buy something for myself, and the owner starts to bad-mouth my buddy. His supplier charged him a restocking fee everytime he returned a drive that wasn't actually broken. Yadda, yadda, yadda. Well, it turned out that the first thing he did every time we brought the goldarn thing in, was take the drive out, and put it in his test system.
So, I visited my buddy, and I tested his power connectors. Sure enough, the one that kept being used to connect the hard drive was unreliable. Something had happened to the hooks meant to hold one of the wires in place. You would plug the connector in, and only three of the wires made a firm electrical connection. Any hard drive connected to that connector developed bad sectors. Presumably it was supplying intermittent power. Maybe it was arcing.
The owner/technician at the mom-and-pop computer shop never found this simple problem because he never tested the drives in situ.
But I wasn't smart enough to learn from his mistake. I built a computer, as a favour, for someone I didn't really know, to pay off a family obligation. I used some stuff I bought used, but which I had tested. Then I got calls that it wasn't working. I thought I test that hard drive! Where did these bad sectors come from? So I replaced it with my own hard drive, bought new, which I knew to be reliable. It developed bad sectors too. Sure enough, it too had a white power connector with a wire with crimp on hooks that didn't work.
Now it is the first thing I suspect if someone tells me their hard drive is developing bad sectors.
And even when they do provide a good electrical connection, what about the times the mechanical connection they provide is order of magnitude or two too secure?
I wish all our peripherals used the smaller power connector used on 3.5 inch floppies.
I had no idea that there was any need to connect anything to British Navels. I had an English girlfriend 20 years ago and don't remember anything about any _electrical_ connections anywhere. Seemed like a pretty standard bellybutton to me. It this part of some new broadband in the womb initiative?
The boots (to prevent tangling) are easy to come by, but they cost $0.082/pair and that would cut into the cable manufacturer's profits.
Give me my freedom, and I'll take care of my own security, thank you.
How many electrical engineers does it take to screw in a light bulb?
No, I don't have an answer to that, but Ira Flatow's book They All Laughed has an interesting history on the rivalry between George Westinghouse and Thomas Edison.
Among the information is the tidbit that Westinghouse and Edison had different types of connectors for their light bulbs. Edison being the crafty type gave away adapters so you could insert an Edison bulb into a Westinghouse socket. The genius of it was that the adapter could not be removed once inserted, thereby requiring you to buy Edison's bulbs. That's why we screw in our light bulbs (Not that kind of screw, you perv!) and the connector is called an "Edison" base.
Apologies if this is only slightly correct; I don't have the book in front of me at this moment.
Give me my freedom, and I'll take care of my own security, thank you.
Making finished fiber cables isn't really that tough. I can make a fiber cable almost as fast as I can make a cat-5 cable... the extra time involved comes around when you have to polish the fiber end, so it gets a really good signal through. That can take a looooong time to do a good job, whereas the cat-5 cable is done the instant you crimp it down.
Whoever stated that signature sizes should be limited to one hundred and twenty characters can just go ahead and kiss my