Operational amplifier - the Popularity of the operational amplifier as a structural element in analog circuits stems from its universality. By using negative feedback by changing the characteristics of the feedback circuit of an operational amplifier to change its gain, input impedance and output bandwidth, etc. These parameters are determined using external components and may vary slightly from the factors of temperature, or the tolerance of the designs in the amplifier system. Because these items are versatile and fun to use by designers of electronic systems.
Application of operational amplifiers as blocks of circuits greatly simplifies their design, regardless of whether they used the amplifiers of the integrated circuit that they are given from the discrete elements. Due to the fact that approximately can be considered operational amplifier as if they were ideal differential amplifier, system design simple. Only at a later stage of the project is selected the valid range of parameters for each of the operational amplifier. Such an approach allows not only to simplify the development process of the device and simplification of its simulation in the prototyping phase.
Operational amplifier is a very simplified voltage amplifier with a differential input coupled stałoprądowo. The input consists of two signals – positive and negative nieodwracającego, to dissect. The output voltage is, in turn, asymmetric, and equal to the difference between the input nieodwracającym and converts the amplified A-times (where a is a gain element in an open feedback loop). This parameter is high for most operational amplifiers, and is often 100,000 or more. These systems can operate in a closed feedback loop. By entering into the loop circuit, the matching elements, you can get a system with less gain, nonlinear elements, etc.
Operational amplifier with a closed feedback loop can work basically in two configurations – amplifier nieodwracającego (signal fed to the input nieodwracające - plus) and dissection (the signal fed to the input odwracające - minus). The gain of such a system depends on elements of the feedback loop. In the first case positive and the second negative, which causes the phase shift signal by 180 degrees – that is, its reversal. If the feedback loop there are elements such as capacitors or coils, can change the characteristics of sensitivity, loops, and, consequently, of the entire amplifier. This allows the design of active filters using operational amplifiers. In addition, there are specialized schemes of work op them, such as layouts różniczkujące whether całkujące, sumatory and others.