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LM339 Datasheet and Pinouts Roll Out November 6, 2009

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Today we rolled out the LM339 datasheet page.  Included with the page is a datasheet, pinout diagram, circuit schematic and the first project.   We added a handy feature that will find available inventory and price.  Hope you enjoy it.

The LM339 is a low power, low offset voltage quad comparator.  These devices consist of four independent voltage comparators that are designed to operate from a single power supply over a wide range of voltages.



LM555 Datasheet Page Now Live November 5, 2009

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A new component has been added.  The LM555 datasheet, pinouts, and circuit information is now available.

The LM555 is a timing devices similar to the NE555.  Same class of part.

The LM555 is a highly stable controller capable of producing accurate timing pulses. With monostable operation, the time delay is controlled by one external resistor and one capacitor. With a stable operation, the frequency and duty cycle are accurately controlled with two external resistors and one capacitor.

For the SEO’s, remember back to my test of 4 digit keywords that looked promising?  In reality, they bomb, very little traffic.  So I have replaced the 7101 and 3075 with the LM555 and  new part I will announce on Datasheet reference soon.

Joomla SEO: Day 15 Results in Google October 23, 2009

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DatasheetReference.com was rebuilt and published in Joomla 15 days ago.   Since then the site has been stable in the eyes of the GoogleBot.

I added a red line showing when the site launched in Joomla.   You can see how it has tracked on Google Page 1 since.

Overall, I think this is great news.   I was worried Joomla would damage the ranking but so far this doesn’t appear to be the case.   The advantage of Joomla is that now I can add new content to the site in minutes – and content is king.

Joomla SEO Experiment: Day 15

Joomla SEO Experiment Results October 19, 2009

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Let’s recap.  We hand-built DatasheetReference.com using a variety of SEO techniques.  It scored well and quickly.  We were particularly interested in the page on the LM317 Datasheet.   Read the earlier blog posts for what we did.   Next we rebuilt the site using Joomla.  Can a Joomla built site rank as well in Google organics as a hand built site?   Joomla is a powerful tool and not too difficult to set up but it also limits your control over details in the site that are the bread and butter of SEO.

We are now 12 days live with the Joomla based site.  Google has crawled it and it has settled.  After bouncing around for a little bit the site now is ranking in virtually the same place as the original.   There are a few very high competition keywords that slipped but these were not scoring page 1 or 2 in either version.

The charts below summarize the effect of the change for Joomla SEO.  Days named ‘Jday’ denote the Joomla site was live.

Joomla SEO Experiment Results (Google Page 1 Details)

Joomla SEO Experiment Results (Google Page 1 Details)

AT89C51 Datasheet Goes Live in Joomla SEO Experiment October 9, 2009

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Check out the new AT89C51 part covered in Datasheet Reference.   This is the first section added in the Joomla SEO Experiment environment.

Pretty cool.  It took less than 1 hour to create the section, including getting all the content, menu creation and adjustments.   XML sitemap was automatically updated in the XMAP module.   I manually updated the other sitemap.  Both were resubmitted to google.

Big Change. Joomla SEO now part of experiment. October 6, 2009

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It’s day 55 and DatasheetReference has steadily grown.   The keywords have climbed reliably in the ranks and held steady.   The pinging I’m doing to Google Webmaster for new sitemap submissions has not caused any reduced ranks, contrarily it appears to be helping get more pages re-evaluated as I make changes.

Why Joomla?  DatasheetReference.com had one big drawback.  It was hand coded in HTML and CSS.  Gave me lots of flexibility for SEO experiments but also made it time consuming to update.   So I recreated the entire site in Joomla!

There is a bit of learning curve to Joomla.  I created 3 proto sites with Joomla to get the feel of it and figure out which plug-ins I wanted to use.  One tricky bit was figuring out how to control URLs and Metadata.  Getting sitemaps built and all is another world altogether.  But I did it.  Time invested from first visiting joomla.org – about 25 hours.

The net is I can now update the site in less than 5 minutes!  So can you, I created a page submission tool so anyone can contribute content.   I still need to verify they fit into the SEO techniques I’m applying before they post but join in!

I have also created a lite set of documentation of the Joomla specific SEO techniques I’ve applied on the site itself (see the footer).

Now, I’ve been enjoying the steady growth of DatasheetReference organic traffic so this full renovation is causing me some great consternation.  I fully expect Google to flip out and go whacky on me in page rank.   I have no idea how it deals with Joomla but that is the purpose of an experiment.

Boldly into the unknown we go!

Solar Battery Charger Using the LM317 October 1, 2009

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I bet you’ve been wondering how to build one of these!  Well, now you can learn how on the LM317 Datasheet section of DatasheetReference.com.

I hate to give it away in this blog but here is a snippit.

In this example we will make a solar charger using a 6 Volt 250ma Solar Panel to charge four 800mah AAA batteries. The batteries can be put into a couple of 2 x AAA battery holders and wired in series (link the positive output from one battery holder to the negative of the other).

This gives us 4 x 1.2 = 4.8 Volts with a capacity of 800mah – therefore we want a charging current of around 80ma. According to the table above, a 15 Ohm resistor gives a fixed current of 83.3 milliamps which will be perfect.

555 Timer History Now Included September 30, 2009

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You can now learn the history of the 555 Timer IC in an interview with Han Camenzind, the inventor of the 555 Timer.   This may be the most popular chip ever invented.  Worth a read.


Hans, let’s start the Oral History with your recollections of the initial success of the 555 integrated circuit.

That 555 family was a total surprise.  I wanted to make it flexible, that was the whole purpose, but I didn’t realize it was so flexible.  There are applications now that still sound crazy to me.  And the quantity!  In the second year it moved to the largest quantity sold of any IC and it has stayed that way for 30 years.  The original application was as a timer and oscillator, but it has moved well beyond that.

According to the IEEE Spectrum article you wrote on the 555, there was reluctance at Signetics to invest in this product.  Is that right?

The engineering department at Signetics  – yes, they were a bit stodgy for a semiconductor company.  They were at the forefront.  They had tried everything.  It was a surprising reaction, and it was simply a reflection of the turf.  You know, they were designing and making operational amplifiers.
Was that their primary business?

Yes, the primary linear business, although I think the digital portion (RTL and DTL) was still much larger. For the linear, op amp was king.  So they figured that if I designed a circuit that replaced one or two op amps, that would cut into their sales.

Sitemap Updating Frequency September 30, 2009

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I’ve been looking into the potential of recreating datasheetreference.com on either Joomla or WordPress.   I’ve installed both now.   I like Joomla, it’s got quite a learning curve but looks powerful and flexible.   WordPress is not so powerful but easy.  But here is what I want to talk about today.

WordPress updates can be reflected in Google in less than 1 minute!   I’ve experienced this and that’s why I use this blog to promote pages in Google.   In WordPress there is a nice little plug-in called the Google XML Sitemap Generator.   This little bit of PHP code automatically updates your XML sitemap whenever you make a change, then it reaches out to Google and tells it the sitemap was updated.  I’ve been working under the assumption that poking Google with sitemap resubmits is a bad thing.   Maybe the reverse is true.

This makes a lot of sense.  Google is looking for lively sites.  Not with little changes but with new content additions (like blogs).   With this in mind, I’m making content additions into pages of DatasheetReference.com that I want to promote the most (based on analytic of keyword activity) and updating my ‘last changed’ data in the sitemap.  Then I resubmit into Google (if you haven’t done this, it’s literally just a button you press on Google Webmaster)

Let’s see what happens.

Pimp my 2n3904 datasheet! September 15, 2009

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You know what I mean.   Prime the old google pump for the 2n3904 datasheet and circuit information page.  This particular part number is pretty hot on the Big G so it will take some doing to hold a competitive position.  I have faith.

Yesterday rankings and traffic to the site drove new highs.   All good stuff.  Will it last?  Will I?
Also, on the pimping strategy, there are no guarantees.  The BC547 spec I promoted have not been picked up in Google but they were discovered by Yahoo!  Maybe dormant Yahoo is starting to rumble.