Electronic components

To whomever might know the answer:

Wanting to embark on my own projects, how does the creator of an electronic apparatus know which component to use when compiling circuits and why?

To start, I was wondering about,
resistors, transistors, convertors, transformers, diodes et. al.

I would eventually like to know how computers work, TVs (which I still do not understand how images can be transmitted through electromagnetic waves), calculators and other electronic devices.

Convertor-
First, if one were to create any electronic device the first item would be a means
to covert the AC circuit to a DC circuit. What is the name of the component? a convertor/transformer? How do they work?

Resistor

Next, in circuit diagrams I see resistors throughout. I know that resistors slow down the current but, why is there a need to slow the current? and how do you know how much resistance to use?

Unknown Component

Is there a component that does the opposite of a resistor and make the current go faster (amplifier)? Why would you want the current to go faster? I believe an amplifier serves a different purpose but am not sure. I think it amplifies sound.

Unknown component?

The next component I think is a diode, which which forces the current to go in one
direction but, not in the reverse. Is that correct? Do currents have a tendency
to go backwards? It does not make sense that currents naturally do that?

Finally, I know that transistors are the basic building block in creating logic circuits. Out of all the components I have a better grasp on these. I have a book from Radio Shack that shows me how to put together AND, NAND, OR and NOR circuits using transistors. No need for an explanation but do you know a good book that shows you how to create each circuit and gives a good explanation?

Any help would be appreciated.
Thanks for enhancing my budding passion.
John O.

 

You could not do much better than read the tutorials on this site

http://www.allaboutcircuits.com/

They will explain just about everything you need to know.

 

The Scotsman speaks the truth. The tutorials here at All About Circuits are very well written. They're just about perfect for a hobbyist trying to learn on their own.

 

Also, Radioshack or your local book store might have book on Introduction to electronics. If you have any questions or dont understand something you could always ask them here.

But if your really serious, try a local college (community or university) They are bound to have a course in electronics.

 

as u have requested to suggest a book dealing clearly with the construction of the circuits, i m gonna tell u about a softwae which helps u in this regard..

there is a software by name AKNM circuit super solver, the details of which is given in the site i have given below
www.circuit-magic.com

i will be glad if u find any usefulness in my suggestion. i feel sorry if u have already tried the way.
pretending to be ur friend,

vijeth.k.sastry