transistor Overheating

There were a number of pages added a few years ago that covered temperature derating of transistors. The pages either covered power derating for air temperature or component case temperature. Anyway none of those pages are doing very well, in fact most don't even get a page-view per day.

It's not like I'm going to remove the pages or anything, but I would like to see more activity.
Transistor Related pages:

2N3441 NPN Transistor.
2N4931 PNP Transistor.
2N5003 PNP Transistor.
2N5002 NPN Transistor.
2N6691 NPN transistor.

In the hope that some day they might start doing better I keep up-dating them, although after 2 years of updates it appears that they may never take-off. These are links to pages that were never mentioned in this blog, so they are linked now. There are a number of others that have never been linked, but what's the point.

There are groups of other pages that don't do that well either.
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IC Circuit Functions

I was checking page visits for the year and found a number of new pages not getting any page views, and that have not been blogged about yet. I'm sure there are more but these pages received under 10 page views for the year.

Under the IC Functional Schematics;
Dual Input NOR Gate.
Dual Input XOR Gate.
8-Bit Latch.
MICA Capacitor Part Marking.
Styles of Capacitor Trimmers.

It's a bit late for any of these pages to help with the year end numbers, and the fact that they received less than 10 page views means they wouldn't put a dent in the numbers any way. But I'll blog about the new additions, but I think I added these pages a few months ago. I don't even think these pages will end up with 365 page views next year either.  However sometimes is nice to have a page to round out a topic, it not really just about page views.

Glue Logic Functions

About five months ago I started a new section covering basic IC functions. Of course when I started it, the section only consisted of a few pages but every month of so I add another page. Better yet I go back to one of the previous page addition and add more data.

So a week or so I added a new page covering the 74L121 Monostable Multivibrator [also 74L122]. In addition a sub page to hold the 74L121 Timing Graphs, which were a bit larger to fit on the same page.

These new pages relate to a few others already listed; Transistor One Shots, and a CMOS One Shot IC, and the 555 One Shot.

I think the newest page before that covered Hex Inverter ICs. Before that I think it was Bus Transceiver ICs. The point is that the section is slowly growing in size, and content. Engineering Topics home.

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Why are pages getting no visitors

So I'm checking pages, just to see how they are doing this year from last year. Some aren't doing well with a drop in page views while other pages are just new.

Rotor Diagram, 2 month old page with just 5 page views.
Sample and Hold Definition, I think another new page with 5 views.
Distortion Definition. Yet another 3 month old page with no page views.

I'm using Google Web Master Tools to check page views, and there are misspelled pages getting more hits than these pages. Of course the misspelled one just show a 404 page not found.

Again two more new pages with only 7 page views. The real issue is that half of those page visits must be from me. So the rule is adding a new page may not bring in any new visitors to the site, at least in the short run. Having to wait two or three months just to get a few page views takes a little planing ahead, or at least not really needing additional page views any time soon.
Shrouded Header Definition. does not appear to be index yet
Unshrouded Header Definition. may not be index by Google yet either

Besides being a new page it appears that the few pages covering MIL-STD-100 are doing the worst or at least showing a decline in page views over last year.
BNC Adapter Definition, with maybe 15 page views.
None of these new pages have any incoming links, so the low views also indicate that no one already on the site are viewing these pages.
SCSI Interface Diagram. maybe 20 page views.
They also don't appear in a Google search yet which also indicates they may not have been spidered by Google yet. Google reads between 300 and 500 pages a day and I only have maybe 2000 pages, so you would think that within a week any new page would be spidered. However this two month old page does show up; What is a Tee Connector.

So I guess my advice would be to wait six months before a new page starts bring in any additional page views. And that only counts if the page has something to offer, some of my new pages have very little text which is what the search engine needs to rank a page.

How to Mount a Resistor

I added a new page to cover some issues and things to consider when mounting a resistor to a Printed Wiring Board; as Resistor Mounting. This new page compliments a number of other resistor related pages including Resistor Lead Length, and the dictionary entry on Resistor Mounting Considerations.

Most of the PCB mounting issues should deal with through hole resistors and not surface mount resistors, but I'm not done writing the page yet. In most cases mounting issues for surface mount resistors is provided in the data sheet, which isn't true for through hole resistors. There are just to many ways to mount through hole resistors to include all the different variations in the data sheet.

I'll keep working a bit on the page today and then get back to it on the next time working that section of the web site.

Doppler Shift Frequency

One of the new pages added a few weeks ago but never entered here related to Doppler Shift Definitions. I think the only page that links to it is the Doppler Definition in the dictionary of Radar terms. However because these new additions have not been crawled yet I can't be sure.

Anyway I came across the page so I listed it here, but it was added a week ago..

What is a Varistor

Added a new page to better cover the Definition of a Varistor. I had a graphic of the body of a varistor along with its dimensions and I figured it would be better just to place it on a different page, instead of trying to fit it on a current page. So the page has a few graphics and so far the same definition that was already on the site.

There are a number of pages that link in; Companies that make Varistors, Resistor Definitions, Definition of a MOV, and the original Varistor Definition. Of course the Varistor page was also added the site map which holds all the pages address located on the Engineering Site. The site-map is also located off-site, at another web address.

So that's not a bad start with four incoming page links, this blog posting, an external link from the sitemap and a few graphics. Ok, not that much text, that will change in time. Better than a lot of other pages just starting off.

FMVSS138 Tire Pressure Monitoring System

I was scanning the web yesterday and I came across a new vehicle interface, or maybe a vehicle system. The new interface is called the Tire Pressure Monitoring System or TPMS. The TPMS standard requires cars and trucks to have an early warning system to alert the driver that one or more tires on the vehicle is below their rated tire pressure. The standard went into effect around 2006, but this was the first I ever heard of it. I drive a 2006 Ford Mustang but I don't remember ever seeing it light, so it didn't make it to my model year.

The links pointing to the page include a 'T' Buses page, Electrical Interface Buses page the Engineering Acronyms page and the Definition of Torque page [first term on the page].

So we get another idiot light on our dash-board. However the TPMS light shows a tire to indicate a 'flat' instead of the engine-symbol light used by OBDII which nobody could ever figure out [check engine]. Now TPMS really indicates low tire pressure and not a flat, but one of the possible symbols appears to be a flat tire

Now it's not really an electrical bus, but it could be an electrical interface so that's why I listed it. I also added the spec to the web site so I wouldn't have to try and figure out what it was a few years from now. Apparently this standard does not really depend on any defined electrical or physical interface, it just has to perform its function.

74244 Octal Buffer

Added a new page to show some details regarding the 74244 Octal Buffer. I was adding the page to have a link of one of the interface bus pages, but now I can't remember which interface uses the 74244 buffer. This particular buffer is a 74HCT244 which comes in a 20-pin PSOP, so a link from that page points to it too.

A link also points in from the main Functional IC Schematics page, and the individual page that covers 16-bit Buffer ICs. Like all other new pages I also added a link to the Engineering Sitemap for the Engineering Web Portal.

The link text used for the last two links are used so the search engine sees something other than a link to 'home' or 'sitemap'.

Logic True Tables

I added a new page to hold a Glue Logic Truth Table covering each of the standard logic functions. The graphic already resided on the web site but was accessed by link to a graphic stored out on Picasa. So no new data was added, just moved onto a new page to hold the graphic. So far the new page is linked from the two other pages that had already pointed to the graphic; Definition of Triac [first term on the page], and the page on Glue Logic Timing.

So the Engineering Portal gets a new page, but at the same time it should be a page that will see little if any visitors. It's a common search term with no page text so maybe it will get some internal traffic, but should not see any from a search engine.

The point was not to generate a page which will never been seen. The original graphic was a 100k bit-map file stored out on Picasa, while the new file is stored on my server and only takes up 30k bits. So my server will see a 30k hit each time the page is viewed, it was zero while the pic file was stored off-site.

It's Google's view that a file on another server requires another DNS look-up [to find it] which slows the site down, and of course the new file is 70k smaller. Google started to also rate web sites on speed in addition to all the other things Google rates a site on. So this change makes the site appear faster to Google [a computer], but a visitor would never notice.

It's also better to have a picture embedded within the site and not just use a pointer out to some other server that holds pic files. The attached graphic is a pic of an AND gate and the true table for that AND gate.

Composite Video Connection

I added a new page to cover Composite Video. The video interface was always listed on the Video Buses page, but because there were to many graphics associated with Composite Video I moved the topic to a new page. The link was also added to the Cable Buses page, Interface Buses 'C' and the list of all Interface Buses.

Except for the graphic no new information was added, this is an out of date interface. I still use it to connect to my older VHS tape decks, but I really stopped using the VHS stuff years ago.

I didn't check for any other page to page links pointing to the Composite Video topic, because the links on that page still work, or point to the new page. The attached graphic is one of the Sony Stereo AV receivers I have, I think this one is a 6.1 channel amplifier. I also have another 7.1 Sony receiver which is just about the same.

The receiver has 6 video channels using the Red/White/Yellow Composite video, including; TV/SAT, DVD, Video 1 and Video 2 and a single Yellow composite video connection for a monitor. Three channels of component video are also shown [Green/Blue/Red].

Low Profile BGA packages.

I added a new page to cover a Low-Profile Ball Grid Array or LBGA. For some of these pages I provide package dimensions, but I didn't bother this time. I'm not even sure if the exact height of an LBGA is set or if it's more of an industry standard.

A related page covers a normal Ball Grid Array. Right now the page is a changed copy of the BGA page so I still may need to make some changes. But the important thing is that I got the new page added tonight before I got side track with fixing some other page. The new page is linked off the page that covers Surface Mount IC Packages.

Although BGA style packages are not used for processors in PCs they are used for a number of other components within a PC. Pin Grid Arrays are used for PC processors, while BGA style devices are used for memory and chip sets.

However BGA devices are used to great extend in industry, not because they always have more pins than a PGA but because BGAs are surface mount devices. Normally it's preferred to have all surface mount devices or all through hole devices during board construction.

High Power Transistor Packages

Transistor packages usually use the nomenclature TO-xx, where TO stands for Transistor Outline.  There are a number of transistor packages that will handle high power or high current, but it also depends on the semiconductor inside the packages.

A number of different transistor packages have been added over the last month, several can handle higher power loads. One package style is the TO-3 flange mount body. The TO-3 style dissipates a lot of heat because of the large metal package and because the metal flange is normally mounted to an even larger metal plate to dissipate even more heat. The most common TO-3 package holds two leads, with the case acting as the third terminal. Two additional new TO-3 related pages were added; the first a 4-lead TO-3 package, and the second an 8-lead TO-3 package.

Another through hole style high power package is the TO-220, although this one has a metal tab to dissipate heat. The 3 terminal package already resided on the site; however a 5-terminal TO-220 and a 7-Lead TO-220 package were added. The 7-leaded package has staggered leads, and there's an additional 5-Staggered Terminal TO-220 package to compliment it. Either of the new packages are designed to hold more than just a single transistor or FET; operational amplifiers in the case of the TO-3 package or regulators in the case of the TO-220 packages.

The other high power transistor case is the TO-263, or the surface mount version of the TO-220. There's a 3-terminal version, a 5-Terminal TO-263 package and a 7-Terminal TO-263 package.

It's easy to determine the number of pins required for a particular package, normally the function will dictate the number of leads. However it's a bit harder to pick the correct package style. So these are a few of the transistor package styles designed to dissipate high heat on the site.

Issues Realting to How to Derate Transistors and Resulting Failures

There are two main pages in this section of the web site; How to derate Transistors by Temperature [Power x Temperature], and Diode Derating [Current x Temperature]. An interrelated page details how to read and Interpret Temperature Derating Curves, which works for diodes or transistors.

 One of the new pages covers component mounting consideration, as Lead Length vs Thermal Resistance [power dissipation for leaded parts]. This particular topic shows why lead length is an important consideration in component power dissipation [in addition to increased circuit inductance]. A companion page covers Copper Pad Area vs Thermal Resistance, to address surface mount components.

The second new page covers Junction Temperature and Wirebond Life, the bond holding the wire between the semiconductor chip and package lead frame. Wire-Bond failure rate vs junction temperature is another way to cover the same topic as the derating charts already do; However, some derating curves do cover ambient temperature, heat-sink temperature and case temperature, in addition to junction temperature.

Related links include Maximum Safe Operating Area,
Over the last 30 days I have added almost 30 new pages, but they were so inter-related that I didn't think blogging about them would really help. Either each blog posting would read almost the same or they would have had almost no text. So I'll generated a new xml site-map for Google in a few weeks to catch the new pages, or wait until Google reads the pages their linked from. In the mean time I have been adding links to the new pages to the human readable [html] sitemap that covers the site [Engineering Site-Map].

So these are two of the nearly 30 new pages added over the last month. I may add them in a larger posting rather than one posting per new page.

TO-205 FET Package

A new page holding a graphic of a TO-205 Metal Can was generated. This particular page gives the pinout for an FET, with the transistor pinout to be added later. As with any of the pages, this is linked off the FET Packages page.

SOT-23 Transistor Package

Another transistor package page was just generated. The new page covers a SOT-23 Package [TO-236AA]. The physical dimensions are provided for the SOT-23 transistor package, but I'm not really sure if the TO-236AA would use the same numbers.

The SOT-23 page is linked off the Transistor Packages page, and was added to the Sitemap. That brings about a total of 23 pages in that section.

DO-7 Axial Lead Diode

A new diode package was added today; DO-7 Axial Leaded Package. With the other component packages the DO-7 is linked off the Diode Package Styles page. These packages could be used by other two terminal components, but if they were the 'DO' which stands for Diode would not be used as part of the package name.

3-Terminal TO-247 Semiconductor Package

Yet another new semiconductor package style added today. This time the component is a 3-Terminal TO-247AC Package. The 'AC' portion of the package type defines the package style depicted on the page. There are other styles of TO-247 components with many more than 3-leads. It's my impression that the TO-247 base number defines a  package with an exposed metal plate on the rear of the component that connects directly to the semiconductor die; however I did not take the time to look that up.

The page graphic shows a package out-line and the dimensions for a TO-247AC and gives the pinout for an FET, but the text also provides the pin out for a transistor package.

As with any other similar package, any type of semiconductor could reside in the body of this case; however only a FET and BJT are given as examples. A few N-Channel FETs that use this package include; 2N7563, 2N7564, and 2N7565 [150 to 320 watts].

As with all new page additions to interfacebus, the page gets a mention in this blog, and to the external Engineering Sitemap. In addition there is always at least one internal link, in this case off the Transistor Packages page.

So every new page addition receives at least three incoming links, with two of the incoming links being external to the web site. However at last check the links on the site-map were 'no-follow', which means there is no credit for the link. The no-follow thing is Google's idea, and I have no control over that. Even if the sitemap does no really provide any search engine ranking it still works as a site-map, which is what it really is.

DO-123 Two-Terminal Surface Mount Package

This time a 2-Terminal package was added to the Engineering Site. Under the main page covering Diode Packages, a link to the new page relating to the SOD-123 package style is inculded.

SOD-123 Die Bonding

TO-276 Three-Terminal Surface Mount Package

What is a TO-276 device?
A 3-Terminal Surface Mount Component, shown on; TO-276 Transistor Package.
As discussed on that page the package may be used for any number of different semiconductors, but the term transistor is used in general. As with all the other related packages the TO-276 page is linked off the Transistor Packages page.

There's not much left to say, as this posts relates to the last two previous posts, which have already covered every thing.

This is the first surface mount package added to that section of the web site, all the other pages cover some type of through hole package. However I have had pending data on several other surface mount styles but the data has not been added yet because I been working other site issues ~ I'm not sure if I can add yet another package type in the next few days or not. Of course the Site-Map was also up-dated.

Transistor Die Bonding

Plastic Transistor Body

Following yesterdays posting regarding the addition of the TO-63 transistor package I added yet another transistor package. This newest addition adds a Plastic TO-226 Transistor, very closely related to a Plastic TO-92.

The TO-226 is a common molded plastic case transistor; however because it's a plastic body it's not really used in any government specifications, so there are no BJT Dearting Curves provided as a link. In many cases I add these component bodies and indicate they are transistor devices, but any three terminal part could reside within these component shapes; including FETs and Transistors, or an SCR, Triac, or 3-terminal references or Temperature Sensors.... Of course some of these package will handle more power than others and may not accommodate higher current or voltage applications. Here is the top level page linking all Transistor Packages.

Both the new page on the TO-226 device and the TO-63 device added yesterday have been included in the Engineering SiteMap.

As normal with many new pages, this one is a copy of a preexisting page on the Engineering Site. However over time I'll add more data as I get back to that topic. The page on the TO-63 started out with a bit more data. I should be adding another related page on Friday.

TO-63 Transistor Package

I just added a page showing the TO-63 Package Style. I'm not really sure how it was missing, because the drawing was being used on a few pages. As normal it's a copy of another page [TO-61 Case], but with a different graphic. Next time I get to it I'll add some data to the page.

The main page that shows a number of different links for; Transistor Cases.

Many of the pages that also use or point to the pages describing transistor packages is the How to Derate Transistors.

In general I indicate that this is a transistor package, but any three terminal device could reside in the package.

The graphic is a B-52 Control Panel, lower deck. 
Much of the gear does not look like it fits, like it's a mix of different up-grades over the years.

Chassis Mount Power Resistor

As part of the page covering How to Dearte a MIL-PRF-39009 Resistor, a new page was added to cover mounting area. The original MIL-39009 resistor page covered power dissipation vs ambient temperature, which is what most of the Component Dearting pages cover. More specifically output power by temperature is normally How Resistors are Derated.

This new page covers Derating MIL-PRF-39009 Resistors by Mounting Area. Or available power dissipation in watts compared to the area of the chassis the resistor is mounted to. This style of resistor is designed to be mounted to a metal surface to aid in dissipating power. So this is one of the few styles of resistors that shows a dearting chart that uses something other than ambient temperature. Although the original page does provide power dissipation vs temperature, the chart covering chassis mounting area is not related ~ use one chart or the other for derating purposes.

For reference here is another chart for Dearting a Variable Wire-Wound Resistor, and another for Derating Resistor Networks. But visiting any of these page links will show all the other styles or package options used and their derating charts. Most of the pages in this section have all the same page-to-page links.

Graphic: 

MIL-PRF-39009 Chassis-Mount Power Resistor

Derating an IC

Added a page to cover Derating Integrated Circuits. I think the page only has two sentences. The new page is linked off the main Component Derating page.

As time goes on, I'll add more information. I also up-dated some of the terms on the Transistor Derating page.

The entire derating section is increasing in page views, but not by the amount of time I've been putting into them..

555 Projects

A few weeks back I added a few more pages related to the 555 timer. One circuit uses additional passive components to compensate for the tolerance of the external capacitor; 555 Timer Tolerance Compensation. The second page covers a Reducing Frequency 555 Oscillator. Both circuits are connected as Astable Multivibrator circuits.

Both pages were added to the engineering site map, but it does not appear that either page ever made it to this blog. I only noticed because both of those 555 pages have only received 2 visits in the last two months. It's almost like neither page has been index by Google? However I think the pages were only added 3 weeks ago.


For what ever reason my computer is slowing down to a crawl so I'll end this post and re-boot. Although I think the connection with the internet is going south. But I don't really want to reset the modem because a few of the open pages won't like it, including this blog as it auto saves about once a minute.

-- Ok that work, must have just been a memory leak.
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Resistor Networks

I went a head and added another page for a 20-pin Resistor Network. I added the link  to a number of pages in that section, so many of those pages got updated. A 20 pin through-hole DIP seems like a pretty big package for the termination the package offers, but I guess if you have the board space.... Seems like the BGA package added the other day would be a better alternative. But of course the resistor arrangement is different, at least for the example provided.

I don't know what the application is for because the resistors seem like odd values, but there must be some common usage otherwise they wouldn't make it.

So any way it looks to be about 17 pages in this section, at least with the page address starting with resistor-network. All together they bring in a few visitors to the site, and most of the pages have a 50% bounce rate.

Resistor Array BGA Package

A new page was just added to cover a BGA Resistor Array. The new Resistor Array is linked off the main Resistor Network page, which really covers a resistor network in a 16-pin DIP. I also added a link off the page covering Resistor Array Manufacturers, cause it seems like many of the other resistor network links are on that page.

I also added the page link to the SiteMap for the web site too.

None of these pages covering this topic are doing well. It could just be there is not a lot of search traffic for resistor network packages.

Looks like the last time I added a page to this topic was on Jan 12, as Resistor Networks. Then on Dec 3 as a DLCC Resistor Array. I've been slowly been added to this topic over the last few months.

I also up-dated the new Google search bar, if you happen to be following the other blog. The site search should work the same but the search bar looks a little different.

Panel Mount Fuse Holders

I added a another page the other day, but because I didn't think it would ever produce any visits I waited till today before I blogged about it. Plus I just used all the other related links in the last posting. Anyway, the new page addressed Panel Mount Fuse Holders. Much of the text is a copy from another page, so until I update the listing it will never do well.

I also added another page which contain zero text; Panel Mount Components. Not sure why I added this page, but it is a new page ~ it will be one of those pages that never gets 365 views a year, I already have to many of those.

As with the other new additions, the new page address have been added to the html sitemap. Although they will not be added to the xml sitemap used by the search engines, as I only up-load a new xml sitemap every 3 months or so. But Google should be able to find the new pages regardless.

I still have a number of pic files I want to add to the site, so the next new page address will relate to one of those graphic files I have.

Chassis Mount Fuseholders

Added a few new pages to Google-sites today to hold some graphics of; Panelmount Fuse Holders, Extractor style Fuse Holders, and a different view of a Panel-Mount fuse holder.

Now I don't normally add a blog posting for new pages to google-sites, but I had added a few new engineering pages to interface-bus and listed them within one blog posting. Not so bad but I use the Blog Archive on the left of the page to count the number of new pages. So the count is off when I add more than one page to a posting. Any how I'm using this posting to address pages on another site to make up for a lack of counting on the main site.

There are a number of pages related to Fuses on the main site, those graphics were a bit to large to add. So;
Fuse Vendors.
DC Operation of Fuses.
Fuse Holder Manufacturers.
Fuse Holders in Chassis Design.
Fuse Derating Recommendations.
Fusible Resistors.
Fuse Definition.

There my even be a few more pages related to fuses, but these have the highest ratings in a site-search. Oh the newest of the pages, Fuse Blocks, is doing the worst with only 13 page views this year. The next worst is the page relating to panel mount fuses used in chassis design.

Capacitor Characteristics

A new page providing a graph of Altitude vs Capacitor Operating voltage was added. Of course it shows the capacitor case sizes which kind of also define the operating voltage. A small amount of text was also added to support the chart, but it's not much additional data yet.

Another new page was added to address Capacitor Insertion Loss. The Insertion Loss page is linked off the capacitor dictionary page starting with the Impedance Definition. This page has even less text than the other new page, but this always changes over time. The interesting thing is that the site analytics does not even show any page views yet, and I generated this page three days ago.

I also added both capacitor pages to the engineering site-map, keeping that page up to date. The site map lists all the pages contained on the Engineering Web-Site. I also found a few duplicate entries in the site map, so those got deleted, and I also added a bit of supporting text to some of the page listings.

So it appears that the capacitor dictionary section contains 19 pages, with some number of supporting pages. Of course there is also a number of pages that discuss characteristics of capacitors, sizes, MIL Spec, tolerance and so on.

555 Circuit Diagrams

Yet another 555 schematic was added yesterday. Another Astable Multivibrator 555 circuit, linked off the main 555 Timer Introduction page. This one uses to different circuit paths two charge and discharge the timing capacitor.

I've been calling the listing a Individual Pulse Width Adjustment circuit, but maybe a High-Low Pulse Width Adjustment circuit would be better. At any rate it's a variation of an Astable 555 configuration, but with each of these circuit additions it has more and more circuit elements.

I just generated this schematic graphic, but I think I have one other, so I may yet start another related page address ~ about another 555 circuit.

The next post will be about Capacitor stuff, because I added two other pages the other day but have yet to blog about them.

Definition of Capacitor Terms

A few new pages have been added to the dictionary of Capacitor terms. The first new page is the Definition of Insulation Resistance, which is linked off the page starting with the Definition of Impedance ['I' to 'L' terms].

While the second new page covers the Definition of Failure Rate, which is linked off the page that did start with the Definition of Farad ['F' terms]. In addition a link to the Capacitor Failure Rate definition was also placed on the page covering How to Derate a Capacitor.

A number of pages in that section were also updated to include both pages in the 'D' portion; Definition of DC Leakage and Definition of Dielectric. Also the Definition of ESR.

I also added the links from the new pages to the HTML Sitemap, to keep that up to date. The sitemap was just updated yesterday to include all the page additions over the last few months. Of course the sitemap lists all the pages contain in the Engineering Website.

I should be adding a few other sub pages to the Capacitor Dictionary in a few days. Like these pages additions today, they should be a page to hold the graphic of some type of capacitor characteristic.

555 Timer Operation

Following the last post concerning the 555 Timer IC circuits, I added a new page to cover the functional operation of the 555 Timer. This page is written a bit different then the previous pages and tries to explain how the 555 IC functions. Although it does use the circuit setup of a Monostable Multivibrator to explain how a 555 functions, the page is written from a different perspective then the existing 555 Monostable listing.

It does use some of the same text as the Monostable 555 circuit, so I still need to re-read it to fix the text flow; but I did up-load the page today regardless. A few of the same 555 graphic files are reused as well, in addition to a new 555 schematic picture. I have two more 555 circuit graphics, so I plan to generate two more pages today, and I'll be sure to update the page as I add those new links.

At first I was going to have the new page act as a top level topic for the 555, it turned out that the current 555 circuit pages were only listed in passing. Currently the only page listing that references how a 555 functions is the page covering Functional IC Schematics [Internal IC Schematics]. Or not, I just added the link to the other three 555 circuit pages.

Now I've been going to design reviews for 25 years and don't recall ever seeing a 555 IC in any review. That's not to say there any thing wrong with the 555, but it does deserve a mention. So I may generate a page to cover that opinion, regardless of the fact that 100,000's are sold each year. The 555 functional page is already to long, so it's a new topic anyway and gets a new page.

Graphic; IC Multivibrator Block Diagram.

555 Timer IC Circuits

Added three new pages covering 555 Timer circuits. There's already so much info about the 555 on the web, but I'd been wanting to add the 555 data for awhile now. I don't expect much traffic to the pages because of the other web pages but it still my help some one who is already on the site looking for related information.

Now what I did is start one page and then copy that incomplete page into two other pages. That way as I begin to write the pages most of the text does not turn out to be identical. However that leads to copy-paste errors. But the pages start with the correct back ground data. I think I have corrected most of the typo errors, but I'll get the rest tomorrow.

Anyway I added a page that covers a 555 Monostable Multivibrator circuit, which include a schematic, timing equations and a description. The same holds for the page covering the 555 Astable Multivibrator circuit which was added. Then off the Astable page I linked in a page for a 50% Duty Cycle 555 Multivibrator. The 50% duty cycle page may still have typo's after being generated from the Astable page, but I'll fix them. No one should really be able to find these pages yet anyway, so they should be alright for another 12 hours.

Oh all of the pages appear as if they reside in the Engineering Dictionary section. Linked from the definitions of either Astable Multivibrator, or Monostable Multivibrator definitions. Looks like they are also linked from the Timer definition too. I also already had a page covering a 4098 Monostable Multivibrator so I went ahead and placed a link to the 555 Monostable Multivibrator circuit. Other then that I don't see any other pages I could use to link to the 555 schematics, although I would like a few more. It is what it is, more links may grow over time. Maybe I'll generate a top-level 555 circuits page if more schematics get generated.

Graphic: Internal Block Diagram of a 555 Timer IC, 8-pin circuit package.

Passive Filter Definition

Much of the data on Passive Filters has been consolidated onto one page, as Passive Filter Definitions. Unlike most new pages the filter page already has a large number of cross-links coming in. As much of the filter data already resided on the site, but under individual filter definitions. The original definitions relating to passive filters remain, but are now also all listed on one page [for now].

So these filter terms also come with a number of graphics, but they were also being used on the site already.  A number of new terms have been added for filter types, but most are a different name for a filter already listed. Of course it wouldn't be a very good dictionary page if it didn't list all possible terms.

I may update the passive filter listing again this week, but I think I may also add a page for active filters next week. I hope in the up coming weeks the filter page will be indexed and come up first in an on-site search, instead of many of the other page with only a single filter listing.

Off topic comment, although the site visits are up 20% [pageviews blog posting], hits to the home page of interfacebus are down 9%. However many individual pages show a decline over last year, but I would assume many more show an increase otherwise the site would not be up 20 percent.

Key words; Passive Filter, LC, Capacitor, Inductor, Low pass, High pass.
Graphic pic file; A Common Mode Choke Inductor, through-hole.

Switching Regulator ICs

I started a new page to cover Switching Regulator ICs. I already have a few new graphics and some definitions in addition to text about switching regulators.

The new page is linked off one of the Regulator Manufacturers page and the Dictionary page covering the Definition of Switching Regulators.

So far I only have two picture files, but look at my hard drive later for another pic file.

As I get the page on switching regulators worked up, maybe by the end of the week, I may add a page to cover linear regulators. I may be able to come up with a few gifs relating to linear regulators. Oh, this new page is not about power supplies, unless you consider a switching regulator IC a power supply. 

But one new page was added, with two new gif files. There have also been several other pic files loaded over the last week, just not to new pages.

Communication Handshaking

A few days ago I added a page to cover the Definition of Handshaking. The page is an addition to the current definition of a Hand-Shake that was already listed. It appears to be a pretty good start at addressing the protocol on how two devices pass data.

These days handshaking doesn't occur that often, most buses operate a lot faster using a clock. But for what ever reason I enhanced the definition. I'll finish up over the week, with more text and a few more examples.

Google indicates only one page view in the last few days, which would be from me? I also don't see the page come up in a Google search, but I'll check again a few hours after I post this.

CMOS Monostable Multivibrator

I added a new page to show the functional schematic of a CMOS 4098 IC, a Monostable Multivibrator. The page is linked off the page covering IC Functional Schematics. That section currently has 25 pages of functional IC schematics.

A related page covers Transistor Multivibrator Circuits. All the pages are linked off the Engineering Dictionary, for what ever reason.

I also updated the MIL-STD-1553 page too, in addition to many other pages.

Graphic; C5 Galaxy Transport Aircraft, in flight. USAF photo.

Universal Flash Storage card

The Universal Flash Storage card [UFS] is due to be released in the 4th quarter of 2010. The Universal Flash Storage card would be the 'next generation' in Flash Card. I haven't found to much data on the interface yet, if any. Much of the search results return articles from 2007 when the interface standard was first announced. Other than that I found that the transfer rate would be 3Gbps per lane, which tells me it's a PCIe type of interface with multiple serial lanes. So the new page is blank, that's normal. I'll keep looking for some data, the draft specification should be out on the web......

I would guess that if the standard doesn't come out until the end of this year, I wouldn't expect any Flash cards to appear before mid 2011. However there's always a chance that a company is all ready working on a product, under the assumption that only minor changes will occur to the specification at this point.

Now this is not a computer standard. The specification is really geared to storage applications on a camera or cell phone. But you would still find the interface on a PC as a slot in a Card Reader, or generic flash card reader.

Any way I get to generate a new page, 11 so far this year. I just hope I can find some information on the interface before Google reads that new page and finds it blank.......

Here is a portion of one of those articles from 2007 indicating that Universal Flash Storage could replace the many different flash formats on the market now [which they list]; ".. CompactFlash I, CompactFlash II, Memory Stick, Memory Stick Duo, Memory Stick Micro M2, Multimedia Card, Reduced Size Multimedia Card, MMCmicro Card, Secure Digital Card, miniSD Card, microSD Card, PC Card, xD-Picture Card, Intelligent Stick, Serial Flash Module, µ card, NT Card, and SmartMedia card .." There does seem to be a few competing formats.

Press-on Connector Covers

I had a few yet to be used connector cover graphics so I added a new page to hold them.
The new page is called Press-on Connector Covers. The original page covered all styles of Protective Dust Covers. Both pages are part of the section on How to design Equipment Chassis.
This will be one of those page that will never see many page views. Although the page does not have a lot of text, the text it does have is a copy of the original page.

Graphic; Rear Panel Circular Mil connectors.

Wire size and Resistance

I started a new page yesterday in regards to Wire Gauge vs Resistance.
As I get started on it the page my offer a faster alternative to deciphering the larger Copper Wire Gauge table.

Other then that I don't have much to say. I'll keep working on it......

Via Stubs

Started a new page to cover Via Stubs in Printed Circuit Boards [PCB]. The page is linked off the definition of Via Stub, as a read more kind of thing.

A Via stub is a via that runs past the layer a trace is on. For example a trace on the layer 3 needs to connect to a trace on layer five but the via runs from the top layer to the bottom layer, the stub is the portion of the via that extends past layer 5 running to the bottom layer. A via stub is the same thing as a transmission line stub.

A related page covers How to Terminate a Trace.

Anyway, it's a start to cover the topic, I'll keep working on it for another few hours.
Graphic; Plated Through Hole via in a 6 layer Printed Wiring Board.

Definition of Printed Wiring Board Terms

I went ahead and divided up one of the last pages of PWB Terms that was just too long. The new page covers PCB Terms from 'Gr' to 'O'. While the original page now covers terms 'A' to 'Ge' [listed first].
So the section also covers PWB Definitions 'P' to 'R', and 'S' terms starting with Secondary Side, and 'T' to 'Z' terms starting with Tented Via. There is also a side page that covers PWB Classifications, which has received almost no page views.
All the pages are now pointing to the new page addition, but the new page still needs a little work with the side bar which is a bit to long. From the counter stats it appears I started this 6 page section on PWB definitions on July 25th, and have slowing been adding new terms and PCB pics. However; there appears to be many days the section either receives no visits or just a few page views.

I should be adding another page maybe tonight covering High speed vias. Maybe I should write it before I pick a name.

Capacitor Networks

I added a new page the other day on Capacitor Networks, or capacitor arrays and forgot to blog about it. The new page is linked off the Capacitor Dictionary, or Capacitor Array Definition.

The page shows three different Single In-Line Packages, two capacitor networks and one capacitor array, with standard capacitor values. A related page holds the definition of Capacitor Network.

Which for some reason does not have a page rank, not sure why. Looks like this section has 15 different pages of capacitor terms.

Comment; Ya know there is a bad side to capacitor arrays in a single package, like a SIP. Normally you want the capacitor placed as close to some component as possible. Placement becomes a bit hard once all the individual devices are placed or hard-wired within the same component. You can get one capacitor near the area you want it but the others are wired as they reside in the SIP package.

Resistor Networks

Just added a new page to cover 6-pin LCC Resistor Networks. Yet another page showing a schematic and package style of a resistor network. Currently the page is linked off the 16-pin LCC Resistor Network page.
The new page is a Dual-row LCC package, while the current page is a Quad LCC package. However there is a page that covers a Dual-row 16-pin DLCC Resistor Network, but with no new link yet.
The Resistor Dictionary page the covers the term; Resistor Network Definition.

Looks like the page doing the worst is 8-pin SIP Resistor Network (non-standard connections). With a few page views and no page rank.
I may be able to add the link for the new page to the other related pages in this section.
Graphic; Dual Row Resistor Package.

Panel Mount Resistors

Looks like the small section relating to Resistor Definitions contains about 15 pages now. Really a few more pages, but using different page addresses so I don't see them in my Analytics filter just now. The newest page is linked off the definition of Panel Mount Resistor, as Panel Mount Adjustment Resistors.

The thing I just noticed from the page view data is that the last new page added a few weeks ago on
Resistor Encapsulation has received no page views; added off the page, Damping Resistor.

So what I did was add a short definition of a panel mount resistor, and then added more data and some graphics on a new page; the difference between a paper dictionary and an HTML based dictionary of terms.

I did want to mention that among all the other pages relating to resistors, a number of pages were added that cover Resistor Networks, but they were added under a different section. So there are more than 15 pages in this section, I'm just not counting them here.

SEO hint; it took 7 months before this section received more than 100 page views in a month [from March 1 2008].

Graphic; Metal Shell, Panel Mount, Potentiometer.

RFI Filters for AC Power

There's a small section of pages on the web-site covering Equipment Chassis Design. Maybe a guideline on writing a chassis specification or really a ton of recommendations on what to consider when designing a chassis. That index page lists all the topics so the section of interest can be selected with out going page-to-page.

As a sub-topic of AC power modules, a new page was added to address embedded Power Line Filtering.The page has a few words, but not much guidance yet, but I really wrote it late last night. Wow looks like this is page 56 in that section...

Worst page with only about a dozen hits last year; Water Alarm Units. Maybe because it only contains one sentence of text......

Graphic; Open-Source Power Supply picture.

Seven Segment Driver

Following last months additions of Functional IC Schematics. I added a new function showing the internal gate schematic of a BCD to 7-Segment Decoder Driver. The page is also linked of the page covering a few LED Terms. It seems like I had already added a seven segment decoder page but I couldn't find it, maybe I just wanted to add it and never did.

Companies that produce LEDs, and Display Module Manufacturers.

So second new page addition for the new year, and this is blog posting 193.
Page visits are back up to 9,000 per day, and I hope next week will bring them back to their normal 9,500 a-day.

Panel Mount LED Graphics

Like so many pages before, I added a new page to hold a large graphic or pic file.
The new page covers Panel Mount LEDs. Because I already had a page covering LED Terms, it's linked off that page [added Nov. 2007].

Next Time I get to it I'll add some more data, and another graphic if I have one. Of course you could also call a panel mount LED a bulk-head mount or chassis mount LED.

The page relating to LEDs with the lowest page views in 2009 was Edison Base LED Lamp Definitions. Which makes sense, how many people know that the base of a normal light bulb is called an Edison Screw Base. Which also reminds me of the current issue with those LED Traffic Lights. Which happen to use Super Bright LED Components [added in Jan 2008].

When I first saw traffic lights using LEDs and not incandescent bulbs I looked it up on the internet; ending with a blog posting back in 2007 [Super Bright LEDs]. I even provided power consumption data for LED lights [13 watts] and incandescent lights [135 watts]. Well guess what, those LED based traffic lights don't generate enough heat to melt the snow that lands on the glass plate protecting the LEDs. So in the northern states those LED traffic lights just fill with snow until the lights are no longer visible. Opps!

Anyway first new page addition of the year.
Graphic; Panel Mount Green Light Emitting Diode.