whether understanding construction & its inner working of FET is necessary for designing circuits?

crutschow

Joined Mar 14, 2008
25,695
I felt that operation characteristics is enough to design circuits using FET.
I'll be thankful if someone can clarify.
You didn't need to know about the inner solid-state workings of a FET to design circuits with them.
You just need to understand it from a functional point-0f-view and understand everything on the data sheet.
 

hp1729

Joined Nov 23, 2015
2,304
I felt that operation characteristics is enough to design circuits using FET.
I'll be thankful if someone can clarify.
At what level are you going to design. Simple discrete components circuits? No just a basic understanding is needed. Designing new FETs or chips using FETs ? Yes, in great detail.
Is this an engineering course or a technician course? Either answer can be correct.
 

Thread Starter

theprasanthkj

Joined Mar 10, 2016
6
At what level are you going to design. Simple discrete components circuits? No just a basic understanding is needed. Designing new FETs or chips using FETs ? Yes, in great detail.
Is this an engineering course or a technician course? Either answer can be correct.
Thanks. Right now I'm only designing circuits in which I'm using FETs only as a switch most of the times.
 

hp1729

Joined Nov 23, 2015
2,304
Thanks. Right now I'm only designing circuits in which I'm using FETs only as a switch most of the times.
Only a basic understanding is needed. Engineers and teachers might have a different opinion.

I used to teach at the technician level. We would do basic exercises to get to know the transistors. Would you be interested in such stuff?
 

WBahn

Joined Mar 31, 2012
26,326
For most folks it is more than sufficient to understand a FET (or just about any other electronic device) as a black box that has certain behavioral characteristics at the I/O pins (or other means of interacting with it such as optical or thermal). The level of detail that those characteristics need to be known depends on the needs of the circuit being designed, but how those characteristics come about is generally irrelevant. Those characteristics are generally contained in the part's data sheet and part of the art and science of circuit design is being able to decide which of the many pages of specs are important for your design and which can be ignored. As you get into more sophisticated and demanding circuits you will find that just relying on the data sheet information isn't good enough. It might be because, while the information is technically there, probably as a graph, you really need to be able to model some of the fine details mathematically and having an understanding of how that graph results from the intrinsic behavior of the device is crucial to developing a useful model for your circuit. In other cases, you may be using the device in some lunatic fringe application and the only way to model how it is going to behave is to understand, at a very deep level, how that thing works. I worked for a company for year's that designed custom ICs and our bread and butter were the lunatic fringe designs and we were so successful primarily because our president knew exactly how to violate the design rules in order to get FETs to do what he wanted them to do.
 
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