what opamp parameters consider

hi dear friends.

i know that each opamp is suitable for certain application.
can anyone please tell me what parameters i should consider when i want to select an opamp for an application. for example: for opamp voltage follower what parameters are important or for audio applications and etc.

thanks a lot.

In an Fast Moving Consumer Electronics environment the requirment is to minimise cost reliably.

In other environments such as aviation it is usually reliability in extended functional range such as temprature and humidity and changing preasure.

The point being that often the electrical charecteristics are distinctly second to other charecteristics of the context of which the component is in use.

The next thing to consider is the actual application of the Op-Amp is it being used tobuild a low noise instrumentation amd or a high speed signals amplifier.

What you do is start with the charecteristic that is dominant for you application (price etc) and whitle the parts that fall in that subset buy those that meat that requirment etc and generaly stop when you have reached a hapy compramise.

Sometimes this means using a well over rated component for some asspect of the circuit simply because the same component is used else where in the circuit and using a cheaper component would be effectivly more expensive due to "tooling changes" in production and other aspects such as inventory and price break.

Depends upon what are you trying to do....
. If the power supply is a perfect DC voltage source (that is, it gives the same voltage no matter what happens), the op-amp’s output would be solely governed by its inputs. Since there are no ideal voltage sources in the real world, you have to worry about the power supply’s quality if you want the best performance from an op-amp
if you are making operational amplifier.... Real operational have some imperfections compared to an “ideal” model. A real device deviates from a perfect difference amplifier. One minus one may not be zero. It may have have an offset like an analog meter which is not zeroed. The inputs may draw current. The characteristics may drift with age and temperature. Gain may be reduced at high frequencies, and phase may shift from input to output.

for audio application gain of the amplifier is important... A typical op-amp has a voltage gain of around a million so Clearly, there is far more gain than we require, so we must "throw away" gain using a technique called negative feedback.

If u are making schmitt trigger or so....resistor value calculation and hysteresis gap becomes important parameter