Re: transistors: so confusing!!

andrew_h wrote:
I am new to electronics - I have learnt heaps and am enjoying every new
thing I'm learning. I did do Physics in school, but like alot of people
- didnt pay a HUGE amount of attention to things I learnt. Alot of it
has actually come back - now I wish I paid a bit more attention!

Something that has been confusing me no-end, and I just cant seem to
grasp, is how a TRANSISTOR works!!!

I have read many explanations, but they are confusing and vauge. People
have explained like a tap, that a small change in the base current
allows a much larger amount of current to flow through the
collector/emitter.

I cant grasp WHY they are so extremely important - probably because I'm
finding it hard to understand their basic operation !

Any help with this would be greatly appreciated ... this is really
proving to be a stumbling block ...

Thanks..



Why are transistors so extremely important? Because
there are millions upon millions upon millions upon
millions etc in use. The number is so huge its beyond
counting. They are used in almost every electronic
device most people encounter on a daily basis, throughout
the day.


> Something that has been confusing me no-end, and I just cant seem to
> grasp, is how a TRANSISTOR works!!!

Regrading the above, the confusion may come from pondering
"how it works" versus thinking about "what it does".
How it works gets into physics - how material behaves
at the atomic level. It's fascinating and interesting etc -
but not needed to understand *what* a transistor does.

So, look at what a transistor does.

It can be used as a switch that turns things on or off.
It can be used as an amplifier.

In both cases a small electrical source controls
the transistor at its input. And in both cases, the
transistor output controls a separate and much stronger
electrical source.

Damn clever engineers create a wide variety of circuits
that use these two functions of a transistor to do miraculous
things - display your heartbeat on an EKG machine, guide
rockets to the moon, control your microwave oven, create
an ABS system to prevent brake lockup on your car, allow
you to play games or surf the internet on your PC and
on and on and on.

All based on a device that is controlled by a very weak
source, which in turn controls a separate and much stronger
source. Yes, it is important!

Ed
.

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