What are transistors.

[Muneeb]

good idea, i guesse

[fkeel]

nono

they are just different things. just like a capacitor is not better or worse than a resistor. some applications will need a regular transistor and others will need a mosfet.

if I where you I would worry less about what things do, and more about what you want them to do. think of a cool project you would like to build and set about doing it. using any transistor to make a led blink is a fairly pointless exercise anyway. I dont know a whole lot about electronics either, but I have learned how to use a transistor becouse I needed a transistor.... as long as you dont need it, dont worry about it.

p.

[Muneeb]

so i will just keep it up the transistors later, and start my new and first project (a PING))) sensor that will make  like a piano sound each time we put our hand in front of the sensor)   
so lets say bye bye this post for the moment 

[Grumpy_Mike]

Why are we all talking about a  "mosphet", have they changed the rules of spelling without telling me. I imagine a google search for a mosphet will show nothing useful so how about looking for a MOSFET standing for Metal Oxide Field Effect Transistor. This is different from the original junction  transistors just called transistors or to give them their new Sunday name bipolar transistors.

Fkeel
I am dyslexic and so I am very grateful to modern day spell checkers, they are not infallible but they do cut down on the number of miss spellings. So why do people who are not dyslexic not use them. I assume it is just becouse.

Bye Bye post .........

[fkeel]

haha, yes. so am I, grumpy mike. I figure its becouse most of the time I assume that people will understand me... and I am lazy.

I just relized the mosphet/mosfet thing though while reading another post and came back to correct it.

[Grumpy_Mike]

I figure its becouse most of the time I assume that people will understand me

Trouble was for me that for all of my school life this condition was not recognised by the educational establishment so I just got labeled as being thick. When I started as a University Professor this got changed to being dyslexic, I think it was something to do with the salary. I was once asked to give advice to dyslexic students and my best advice was "don't play scrabble for money".

[fkeel]

haha. I actually am pretty good at scrabble. Its just in the act of writing that I fail. The language I learned reading and writing in is german and for some reason english is a *lot* easier for me. Having to write anything in german is just pure horror. Changing to a university which had english as an instruction language and mainly essays as evaluation form (so you can organize, write it well in advance and then take ten days to make sure what you have written is *actually* english) was the best thing that ever happened to me.

(anyway, this is getting very off topic. I will find myself some web based spell checking program though, better than copy pasting into word.)

[Muneeb]

i suck at speaking english, but i write in ensglish.
french is equal to secondry 1 and below. 

[Bill_Kerr]

Muneeb

As you are seeing, there is no simple answer.  It does take some learning.

Check out his web page for what you are trying to do
http://www.sqlskills.com/blogs/paulselec/post/Arduino-figuring-out-transistors-and-associated-resistors.aspx

I found it with a google of "Arduino transistor LED"

When researching you will see there are NPN and PNP transistors. 
The arrow used with the schematic indicates direction of current flow.
They can handle currents from several milliamps to Amps.
They are used in switching DC circuits (on/off) and AC for amplification. 
Input is to the base, as mentioned, the current on the base can be amplified on the emitter/collector
The gain in current (HFE) from base to can be as low as 10 to over 5000 with what is called a darlington transistor

Here is a good tutorial to help you out
http://www.electronics-tutorials.ws/transistor/tran_4.html

Regards  Bill

[Techone]

@Muneeb

Here a basic electronics circuit simulation. It free, you can "buit" basic circuits, so you see what the circuit does and you can download the app.  it is a Java App, the con is can't save & print your work. Here the link.
http://www.falstad.com/circuit/ I hope it help you and it help others. That app help me out to figure things out.

If you want to pay for a better electronics circuit simulation, here the site. http://www.new-wave-concepts.com/ . Anyway, check it out. I have Circuit Wizard Pro, it is expensive, but it is worth the investment. I made a few projects using that software.

I wish a Arduino simulator was available. ( I got VBB, not working right )