Solid State Drive Vendors

Added a new page on Solid State Drive [SSD] manufacturers a few weeks ago. SSD may also stand for Solid State Disk, depending on what page you may check. The page started as a copy of Hard Disk Drive [HDD] manufacturers.

The page still has a few notes relating to HDD vendors, but has many more listings that relate to SSD vendors. There seem to be only two main form factors;
Laptops, at 1.8"
Desktop at 2.5"
They also seem to be supplied with one of two main interface standards;
Serial ATA [SATA], SATA-I, or SATA-II
Parallel ATA [PATA]

These are drop-in replacements to a normal HDD devices, and operate much faster.

The smaller 64GB SSD's don't seem to cost that much any more, at a tad less than $200. However 64GB is almost to small to use as a main hard drive. I purchased a 10,000 rpm hard drive a few years ago as a data drive, so I guess they may function as a non OS drive. I wouldn't attempt to put Windows Vista on a 64GB drive.

I see 80GB and 128GB drives running into the $300 range, still to small to be usable. The larger drives containing 250GB of memory are ranging from $700 to $900, which could be the total cost of a new computer. Maybe by next year the price will come down so most people could purchase one with out any sticker shock.

I found one 8GB PATA device for $100, not really sure why I wouldn't use a USB Flash device at that point.

I also noted that normal desktop PC drives use MLC devices, while server side drives use SLC devices. Definition of MLC.

A related page covers Hybrid Hard Disk Drive [HHD] manufacturers. Hybrid drives have a platter but also contain more flash memory operating as a larger cache. I'll bet these don't stay around much longer than next year once SSD memory prices are reduced.

When to Dearte a Transistor

Copied another page on how to derate a transistor into two other pages that used the same derating chart.

2N4237 Temperature-Power Derating Curve, duplicated to.

2N4238 Derating Graph.

2N4239 Derating Graph.

A few other related pages in the section were also updated

2N3498 Derating Graph.

2N2906 Derating Graph.

2N3634 Derating Graph.

Some of these preexisting pages may not have ever been listed out here as new pages, so this may be their first posting. In any case it's yet another external link generated.

There are three different possible guidelines a designer can use when implementing a transistor circuit. 

1. The engineer may use a generic guideline using a simple Derating Factor;

     Example: Derate 50% up to a maximum junction temperature [Derating Factors].

2. The engineer may use a Linear equation which is more a design recommendation;

     Example: Derate Linearly at 12.7mW/ degree C, above 25C [Derating Recommendations].

3. The engineer may use a Temperature-Power Curve which should be treated as a design rule;

     Shown on any number of pages, [Derating Rules].

There were two other pages up-dated to hold the links for the page just generated;

Guideline to Derating Transistors, and Guideline to Derating NPN BJTs.

Addtional related pages on the web site:

Manufacturers of Transistors.

Transistor Amplifier  Circuits.

Transistor Circuit Schematics.

Transistor Multivibrator Circuit Schematics.

Definition of Transistor Terms.

Additional related pages on this blog:

Rules for Derating a Transistor.

Transistor Derating Guidelines.

Recommendation on how to Derate a Transistor.

Derate a BJT by Temperature.

FET Derating Guidelines.

NPN Transistor Derating Curve.

Power Derating for Transistors.

Rules for Derating a Transistor

Following yesterdays transistor posting, I've added two more pages relating to how to derate a particular transistor. Like the previous post the new transistor pages are near a copy of a preexisting page, that happened to use the same derating graph.

MIL-PRF-19500/539D:

2N6301 Temperature-Power Derating Curve [NPN BJT].

2N6300 Temperature-Power Derating Curve [NPN BJT].

MIL-PRF-19500/545G:

2N5153 Temperature-Power Derating Curve [PNP BJT].

2N5151 Temperature-Power Derating Curve [PNP BJT].

Three other page up-dates then followed;

How to Derate Transistors.

How to Derate NPN Transistors.

How to Derate PNP Transistors.

Which were updated to hold the links to the new pages. In addition each new page links to it's copy that holds the same MIL Spec and Derating Graph.

Also added a new line item to the Transistor Derating Recommendations page, which only provide Derating Equations with no Derating Curves.

It may of taken over a hour to generate the page up-dates but it was an easy way to generate two new pages and add more page to page links.In addition four other related pages were updated:

MIL-PRF-19500/396K;

2N3764 Temperature Derating Graph.

2N3765 Temperature Derating Graph.

MIL-PRF-19500/396K;

2N3762 Temperature Derating Graph.

2N3762U4 Temperature Derating Graph.

So in this derating sections there were 10 page up-dates and 2 new page additions. There were also another dozen unrelated page updates.

Guidelines to Component Derating.

Transistor Derating Guide Lines

Added a new page to cover power derating of a 2N3765 transistor. The page is almost a copy of the page for the 2N3764 transistor because they both use the same derating graph. Links have been added to their related transistors covered by the same specifications; 2N3762U4 transistor and 2N3762UA transistor, both surface mount devices. A reference was also added to the page covering PNP transistor curves, and derating transistors.

A few other unrelated pages were also up-dated, including;

Derating a 2N930.

Derating a surface mount 2N930UB.

2N718 derating graph.

2N1613 derating curves.

2N3055 transistor derating curves.

All the pages provide a Temperature-Power Derating Curve, and some also provide a derating equation. Use one or the other as a guideline for derating the device.

Related pages;

Recommendation on how to Derate a Transistor.

Derate a BJT by Temperature.

FET Derating Guidelines.

NPN Transistor Derating Curve.

Power Derating for Transistors.

Industrial Rackmount Computers

As part of the section on how to define an equipment chassis specification, two new pages were added.

The first page covers Industrial Rackmount Computers. The Industrial computers page provides a few design hints and a listing of companies that produce industrial PCs. The original list of industrial PCs had resided on the Manufacturers of PC Chassis page. The PC chassis vendor page now only holds commercial products.

The second new addition covers Cable Carriers or Cable Retractors. A Cable Carrier helps manage cables between the equipment chassis and the chassis rack. Using a cable retractor insures that the cable assembles bends and moves the correct way as a chassis is being moved in and out of a rack. Cable retractors also insure that the cable does not bind on any thing behind the chassis or within the rack. Within a few days the page will also cover Cable Retractor manufacturers.

Also added two more chassis specifications to the chassis standards page. Of course the main page in the section now lists the new page additions. Two new link additions to the section include; Fuse Derating, and Power Supply Standards. Also fixed the link to manufacturers of Anti-Vibration products, which happened to be pointing to the Rack Leveling products page by mistake.

The purpose of the entire section is to show a novice how to design an equipment chassis, or how to write a specification so an OEM could design the chassis. In any case the pages provide many design hints and engineering guidelines as well as some do's and don't s concerning electrical equipment design.

The industrial equipment design section spans 46 pages with links to other relevant topics on the web site. Don't get burned when purchasing an equipment chassis, review the different section that are relevant to the chassis your designing.

The page covering manufacturers of chassis has a link to the top page in this section.