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.