What is the circuit desighn within op amp?

[Hyperspace2]

I am first year student 0f electronics and communication engineering.
I have a course called basic electronics.
I have already learn't bjt,jfet,mosfet,diff amplifier etc, now its turn of op amp.
And I can't move on without knowing what is within op amp. Pictures shows Triangle and +,- within it. What is the meaning of inverting and non inverting input? Whats the physical meaning. Anyone please help me explain in very simple language. English is not my first language. Thanks in advance.

 

[user091024]

A signal fed into the + input (non-inverting) will produce an output signal that is in phase with the input signal. A signal fed into the - input (inverting) will produce an output signal that is 180 degrees out of phase with the input signal. This is for single ended operation, where the input signal is at one end and the other end is grounded.

If you take a closer look at how a discrete differential amplifier works, it might help.

 

[Hyperspace2]

Thanks user091024 for the reply and also thanks for explaining the meaning of inverting and non inverting input? Can you also explain the inner structure of op amp . Is the circuit inside the op amp too complicated that the begineers shouldn't try to focus at it.

 

[granpa]

http://www.circuitstoday.com/op-amps-operational-amplifiers

http://www.edaboard.com/thread137646.html

 

[Hyperspace2]

Thanks Granpa. I got it

 

[vk6kro]

This is a circuit diagram of the components inside a LM741 opamp.
As you can see, it uses 20 transistors, although not all of them are being used as amplifiers.

It is probably sufficient to say that opamps have huge gains and you probably don't need to worry about exactly how they work internally.

You might like to read about op amps here:
http://en.wikipedia.org/wiki/Op_amp
That is where the above circuit comes from.

 

[Hyperspace2]

This is a circuit diagram of the components inside a LM741 opamp.
As you can see, it uses 20 transistors, although not all of them are being used as amplifiers.

It is probably sufficient to say that opamps have huge gains and you probably don't need to worry about exactly how they work internally.

You might like to read about op amps here:
http://en.wikipedia.org/wiki/Op_amp
That is where the above circuit comes from.

Thanks . The pics are really complicated for me though.

 

[granpa]

the pic looks complicated but it isnt.
if each of the transistors gives 100 fold amplification then
the 2 together give 10,000 fold amplification.

But then you send part of the output back through a resistor (call it R) to the negative input and
thereby self-limit the amplification to 100 fold amplification.

Why would you do that?
I was told that it makes the op amp a sort of 'idealized transistor'.
A transistor that behaves more or less exactly the way you expect a transistor to behave.
It also allows you to precisely determine the amount of amplification by changing the value of R

 

[granpa]

http://en.wikipedia.org/wiki/Operational_amplifier_applications#Differential_amplifier