Operational Amplifier - Need some info

[purifier]

/opamp_trivia_webcast_final.pdf

I was just wondering if anyone could help me with the following:

1. What is an Operational Amplifier ?
2. How is it made ?
3. Why it has got that name ?
4. What are its applications ?
5. What are its limitations ?

Can anyone give a clear idea regarding these ? Whatever I found were just explaining its operation but i needed some interesting info regarding op amps...

 

[rkodaira]

gregorian operational amplifiers pdf

1. What is an Operational Amplifier ?

An Operational Amplifier is a device used in several electronic circuits and it simplifies the design of analog circuits because it can be treated as a block. An Op Amp has two inputs (first stage is a differential amplifier) and one output (in fact it can have more 2 supply pins and offset adjust pins). An Op Amp usually is set with a feedback loop from its output to one of its inputs (negative or positive feedback). Feedback is keyword to use an Op Amp properly, since it has a high gain in open loop but a small bandwidth (frequency response). When you set feedback, the bandwidth increases and the gain decreases (the relationship BW x Gain is constant). Op Amps also have very high input impedance and low output impedance, so it can be very useful to adjust impedances between circuits. The voltage gain can be easily set by adjusting the correct values of resistors in the loop feedback.

2. How is it made ?
It is made of transistors (bipolars or/and fets) packaged together in a integrated circuit. You can see the electrical schematic and the components in an Op Amp datasheets (a lot of transistors and other components). An Op Amp can be made of discrete components and in the past, they were built using electronic valves (tubes).

3. Why it has got that name ?
Operational Amplifier name derives from its application from the past: these amplifiers were invented to be used as part of ANALOG COMPUTERS to perform the MATH OPERATIONS (sum of voltages, subtraction of voltages, multiplication, etc). Since the fact that computation turned into digital system, Op Amps had other application in the modern world.

4. What are its applications ?
So many applications, mainly on instrumentation, audio, etc
Op Amps can be used as signal amplifiers (inverter or non inverter), as adder amplifier, subtractor amplifier, log amplifier, antilog amplifier, oscillator, schmitt trigger, comparator, integrator and differentiator amplifiers, part of A to D converter and D to A converter, buffers and many applications.


5. What are its limitations ?
Op Amps are very close to ideal devices (infinite input impedance, zero output impedance, very high gain, fast slew rate, high bandwidth, no offset in the output).
Their limitations are:
- Output voltage restricted to rail voltages (supply voltages)
- Minimum supply voltages
- Slew rate not infinite
- Bandwidth
- Power
- Temperature range

 

[uladz55]

Hi,
check this book

**broken link removed**

 

[IanP]

Here is more info on op-amps:

**broken link removed**
**broken link removed**

 

[purifier]

These are the best answers i could ever imagine of... Really, i'm grateful to you all... Thanks a lot...

 

[cmos babe]

You can have a better basic understanding of OP AMPS without any knowledge of transistors by reading CHAPTER2 of Microelectronic Circuits by by Adel S. Sedra, Kenneth Carless Smith. All you need to understand that chapter is some basic circuit analysis knowledge

 

[electron_boy]

check this one out
"design with opamp and analog integrated circiuts"- sergio franco

 

[Fried]

More info**broken link removed**

 

[suvendu]

opamp is a high gain differential amplifier.the name suggest ,it performs many operations e.g adder,subteracter,multiplier,integrator,differentiator etc.

 

[irfansyah]

This is my humble opinion about op-amps

1. What is an Operational Amplifier ?
A device with two inputs and one output. The op-amp outputs an amplified voltage difference from both inputs. Ideally, the gain (amplification) should be infinite.

2. How is it made ?
Usually i buy op-amps ICs from stores. There are several popular op-amp IC's, like LM741, TL081, BF327?, etc. I dont know how they are made, i just know how to use them

3. Why it has got that name ?
Because it amplifies signals!

4. What are its applications ?
- Amplifiers (to make weak signals bigger so that it can be usefull for the next stage of the electronic system?)
- Filter (you can make active filters with these)

5. What are its limitations ?
- Gain-bandwidth product
- Frequency response
- Slew rate
- Power consumption
- etc, i'm not so good at this either

 

[shaq]

You can also read "Microelectronic Circuits" by Sedra&Smith

 

[gevy]

Also read book
INTRODUCTION TO CMOS OP-AMPS AND COMPARATORS by Roubik Gregorian

 

[randika]

Hay,

Follow this link also, a nice explanation about OP-AMPS That will really helpful for a novice...

**broken link removed**

cya

Randika K

 

[tony_wu_ad]

Hay,

Follow this link also, a nice explanation about OP-AMPS That will really helpful for a novice...

h**p://www.talkingelectronics.com/Projects/OP-AMP/opamphandbook.pdf

cya

Randika K

The file of opamphandbook.pdf not find

 

[randika]

Yes, that link is not working.... sorry for the inconveniance..

cya

Randika K