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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