Switches and Snubbers

Switches and Snubbers. Part of a series of videos on the design of snubber circuits for power electronics by Rudy Severns. This is a book about snubber circuits for power electronics. Of course, it has several chapters which go into great detail about different kinds of snubbers and snubber circuits and how they work.

We have to remember that what we're doing is applying the snubber to a switch, and we have to understand the switches themselves whether they be as simple as a mechanical switch or some form of semiconductor switch. There are many, many types of switches that are used. In today's world they are primarily semiconductor switches.

What we need to do is understand switches themselves. So, one of the chapters in the book, of which I have a draft sitting right here, will be about switches and the switching action itself, not about the snubbers.

This is going to talk to you about what we want from a switch. It also brings out the important idea that if you take a given switch, let's say it's a MOSFET or an IGBT, and you combine it with a snubber, what you really have is a switch only with greater capabilities.

This brings out the idea of this interaction between the switch and the snubber and the function that it is designed to provide in the circuit.

This particular chapter will go into considerable detail about switches themselves. It's not going to tell you how MOSFET works, but it will tell you how switches work in a very general way.

No book on snubbers would be complete without a little bit of history. Obviously, we can't spend a lot of time studying the history of snubbers, but it is a very valuable thing to look at and to recognize just how long snubber circuits have been in use.

When I have gone back through the history and the papers, the earliest paper I have found is dated 1853. I'm not putting you on. It's written by a French physicist by the name of Fizeau and it was, of course, talking about the problems having to do with mechanical switches particularly in the context of spark generators.

They had the inductor where you interrupt the current in a primary inductor and through a secondary create a spark on the other side. Eventually this became ignition systems, for example, in cars.

We know that in cars the ignition system always has a capacitor across the points. This is because of the inductive switching action. It turns out we can pinpoint when that was invented by Monsieur Fizeau in 1853.

Then, of course, when we talk about the history a little more we can bring it up to date and show the transition from mechanical switches to vacuum tube and gas switches and, finally, to power electronic switches which are basically semiconductor switches which is what the world is today.

It's kind of fun, and there will be some of this in the book just so you can get a feeling for the history which goes back almost 160 years.

Rudy Severns' book "Snubber Circuits for Power Electronics" is available for purchase on the Internet as an ebook in PDF format at WWW.SNUBBERDESIGN.COM

Category:

Science & Technology

Tags:

• snubber
• design
• power
• switches

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is this book available as an ebook