Instructables

Does every URL have a doppelganger?

I lack the knowledge to frame this question properly, so here's an example of a website that has 2 urls for the same page:

This shorter link: http://bit.ly/14kJOhi

takes you to the same page as this longer link: https://secure.campaignsolutions.com/theteaparty/donation_petition_RecklessSpender/Default.aspx?initiativekey=8OMMPHTTTZGG

Does every web page have a shorter URL?  If so, where can I find it? 

No, but there are sites that can create shorter links for you. I think this whole shorter link fad started with Twitter as you are limited to character space and some links get incredibly long. I usually use TinyURL, but there are many to choose from :) 

I think most services are free, but I'm sure there are ones that cost money as well.
bajablue (author)  Penolopy Bulnick1 year ago
Thanks so much, Nikki!

oh... and btw... HAPPY 100!!!! ;-)
100 Instructables.jpg
kelseymh1 year ago
Penelopy should get Best Answer.

But for the record, I would never click on a "tiny URL", since there's no way to identify where you're going to be taken (Rick Roll, spammer, identity theft, virus distributor). Unless you have a good reason to use them, and your own Web site is sufficiently reliable that you can be used to authenticate the links, just don't.
But admit it, rickrolls are just good.
Anyways, check out this vid!

Terminator Salvation – Newly Released Trailer
http://www.youtube.com/watch?v=gvGyS5j9aFY
True, true.

There are services like GetLinkInfo, LongURL, KnowURL (and many others) that translate the short URL back into the long version.
Thank you! I didn't know about those, but now I do.
bajablue (author)  kelseymh1 year ago
Thanks for explaining the downside. I see Scooch uses them on facebook a lot... and I like the way it presents.
jjames391 year ago
In this article we will learn how to make a very simple piezo electric buzzer using hardly any electronic components. Just a single transistor, a coil, a piezo buzzer are enough to make it “buzz” or rather “twit” for you, with an output that may be quite ear piercing.


Circuit Description:

The buzzer circuit described here actually works in a quite unique way. Instead of the normal working concept employed by other forms of oscillators which require resistor and capacitor networks for generating the oscillations, this circuit use inductive feedback for the required operations.

Referring to the figure we find that the transistor T1 along with the inductor forms the heart of the circuit. Basically the coil which is specifically called the buzzer coil, is in fact positioned for amplifying the created oscillations while the actual feed back is provided by the center tap of the three terminal piezo element used for the present application.

When a voltage is introduced in the circuit, the transistor conducts, operating the piezo element across the buzzer coil, however this also leads to the grounding of the base of the transistor through the center tap of the piezo element, this instantly switches off the transistor and in turn the piezo also switches off, releasing the base of the transistor.

The transistor reverts to its original state and the cycle repeats, generating oscillations or the required “buzzing” frequency.

The center tap from the piezo transducer plays an important role in sustaining the oscillations and therefore in this particular design we need a three terminal piezo rather than a two terminal one.

The oscillations produced at the collector of the transistor is dumped into the coil, saturating the coil with magnetic inductions. The coil kicks back the stored energy during the oscillations, magnifying the generated AC across it.

This stepped up AC is applied across the anode and the cathode of the piezo element, which starts vibrating sharply according the pitch of the frequency, generating a shrill, ear piercing sound in the air.

However to make the sound audible at maximum intensity, the piezo transducer needs to be stuck or installed in a special way inside its housing.

For this particular application the piezo element needs to be stuck at the base of its housing which must consist of a hole having a diameter of about 7 mm.

The piezo element cannot be stuck directly over the base of the housing, rather it must stuck and positioned over a soft, pure rubber ring, having diameter 30 % less than that of the piezo transducer. www.cusabio.com antibody drug
Only if the above fixing procedure is followed, the buzzer will sound, otherwise the sound may get choked and fail to reproduce.