Regarding barrel connectors

Hello All,

I am new to the world of Arduino UNO. So, have a basic quesion regarding the power supply: -

Aside from the USB, there is also a female barrel connector (also called a Jack based on the reading I have done so far). My power adapter needs to have a male barrel connector (also called plug??) of size 5.5 mm X 2.1 mm.

The power adapter that I have is this: - http://www.aliexpress.com/store/product/Original-AC-Power-Adapter-Charger-for-PHILIPS-MU18-2090200-C5-9V-2A-3-5x1-35mm-EU/822937_859342176.html

It has a 3.5 mm X 1.35 mm plug.

In order to use it to power my Arduino UNO, I plan on getting the following converted plug: - http://www.amazon.com/Power-5-5mm-Female-1-35mm-Converter/dp/B00MJU9K5A

Will this work?

Thanks in advance!

Regards, Divyaman

divyaman:

In order to use it to power my Arduino UNO, I plan on getting the following converted plug: -
http://www.amazon.com/Power-5-5mm-Female-1-35mm-Converter/dp/B00MJU9K5A

Will this work?

I don’t think so. The adaptor is the “wrong way” around.

// Per.

I think you have the sex wrong. I don't have an Uno but I'm quite sure that the Uno barrel is a male (the one on my RedBoard clone is).

So make sure about the sex of the barrel. If it has a pin in the inside, it's a male.

I think that the adapter that you linked to will work; it's a female at the barrel side so will fit the male.

It's a contentious point regarding coaxial connectors. It can be technically argued that the UNO has a chassis male and you plug a line female into it. That is how I tend to view fittings. Mind you, honestly, which gender does the line fitting actually resemble when you think about it?

This (the original) is the typical "tricky" question where someone has the completely wrong piece of equipment. Why was such an over-priced thing bought anyway? Certainly not for powering an Arduino.

Adapter plugs are not a good idea. The two better ideas are

  • Buy a standard (and they are the standard, the most common size among many) 2.1 mm line socket and solder it onto the cord when you cut off the other and the "python swallowed a walrus" object.
  • Go to your local "Op Shop" and find a $2 phone charger rated at 5 V, 1 or more Amp, cut off the connector after you check the voltage with a multimeter and solder it to pins you can insert into the 5 V terminals on the Arduino.

Now of course,

  • If you don't have a multimeter, stop now and do not proceed on anything until you buy one - a $5 one will do just fine.
  • If you cannot solder things, give up until you find a mate who has the facility (and the skill).
  • Yes, you must be very careful making connections direct to the UNO but - if you are not extremely careful, then carefully place it in a storage box and take up knitting.

The Uno, and others, use a 5.5mm x 2.1mm connector with positive male pin. You need the corresponding part with a female cable end socket. The gender of plugs/sockets should be based on the pins and not the housing. That rule has been corrupted in recent years.

Ok, the barrel on my Arduino UNO does have a pin inside it. I had guessed its a male.

The following link on sparkfun, however, had me a little confused: - https://learn.sparkfun.com/tutorials/connector-basics/power-connectors

It made me conclude that the power barrel is a female one. If you look at the pic in this article, it seems to suggest that the power barrel with a pin is a female one. Maybe I got it wrong.

So, if the barrel on the Arduino is a male (5.5 X 2.1 mm), will the converter cable (http://www.amazon.com/Power-5-5mm-Female-1-35mm-Converter/dp/B00MJU9K5A) serve the purpose? I am not comfortable with soldering and stuff like that (not yet anyway).

One more question: - The power supply has an output voltage of 9 V(which I believe should be fine). But, it has an output current of 2 A. Is that too high? The article here doesn't clearly indicate if it would be unwise to go beyond 1 A (http://playground.arduino.cc/Learning/WhatAdapter).

Thanks for your responses!

Regards, Divyaman

The Arduino only draws what it needs; no problem if a 2A power supply is used

That adapter is not the right one. You need one going from 1.35mm up to 2.1mm.

Sellers are often quoting connectors with the wrong gender terms. They tend to use the housing and not the pins. The Uno connector is male as the center terminal is a pin. The standard convention is that sources of power use female terminals as they can be encased in housings that protect them from an accidental short.

There are numerous switching power supplies on eBay. You might be better off just getting a 9V-1A, or higher current.

The current rating only has to be as high as the device needs, plus a safety margin. A higher rating just means it can supply that value if needed. The device determines what it needs at a given voltage.

I would cut the cable and solder a new connector to it.

They say the power adapter is "original". Well, I have my doubts. Please buy a good quality power adapter from a local supplier in your country. Or buy one for example from Sparkfun or Adafruit. It must be certified to be used in your country.

When a power adapter fails after many years, it should just stop working. The cheap power adapters can catch on fire when something is wrong.

Koepel: When a power adapter fails after many years, it should just stop working. The cheap power adapters can catch on fire when something is wrong.

Or (almost) equally bad - fail to regulate and completely destroy the device which they are powering. I would say slightly (but only slightly) more likely when operating at 220-240 V.

divyaman: The following link on sparkfun, however, had me a little confused: It made me conclude that the power barrel is a female one. If you look at the pic in this article, it seems to suggest that the power barrel with a pin is a female one. Maybe I got it wrong.

The article itself is thoroughly and utterly confused! Having defined the gender of coaxial connectors, it goes on to carefully and specifically define exactly the opposite convention for every other form of connector.

I think the female barrel is on the Arduino board and the male plug is with the wire to the power adapter. The pin in the middle is ignored when naming it female or male. And some call it "Jack".

Koepel: I think the female barrel is on the Arduino board and the male plug is with the wire to the power adapter. The pin in the middle is ignored when naming it female or male. And some call it "Jack".

So you define this as a female "jack":

And this as a "plug":

But sparkfun call them the opposite, saying

The gender of the pins inside the connector is what signifies the gender of the connector as a whole.

:grinning: :grinning: :grinning:

I don't know, now I'm also confused. :grin: :grin: :grin:

Paul__B: So you define this as a female "jack"

She obviously has not had the operation yet :)

Koepel: I don't know, now I'm also confused.

So is everyone, clearly. :astonished:


Boardburner2: She obviously has not had the operation yet

That is a very nasty topic - with vastly more ramifications than this trivial one.

I have always learned and used

pin starts with a 'p', penis starts with a 'p' and hence a part that has a pin is male.

It worked for the original (DIN) keyboard connector on the PC, PS2 connectors, RS232, F and BNC connectors, SCART and RCA and so on.

I don't see a reason why this barrel would be different.

sterretje: pin starts with a 'p', penis starts with a 'p' and hence a part that has a pin is male.

|500x325

Perfect example as the plug body has both sexes so only the pin/socket can be used, (p)eni(s). Note that the connector body is often the reverse of the pin/socket.

Paul__B: image

:D In which case there is no problem if it's male or female; it is hermaphrodite.

And if the Arduino board had a connector like that, the point of sexes would never have been raised ;)

Like a snail in fact.

That was of course the search term I used to find it.

The interesting thing about those connectors is that they work just fine, the polarity is never in doubt, you can add extensions and all - just as long as you never connect two sources (batteries) together by accident. :astonished: