The second question:

The third question (1):

The third question (2):

The fourth question:

Extended data electronic circuit elements, basic unit circuits of linear circuits, integrated operational amplifiers, frequency characteristics of amplifier circuits, feedback amplifier circuits, integrated operational amplifier application circuits and low-power DC regulated power supplies. Pay attention to basic theory, concept description and applied knowledge, strive for simplicity and avoid abstruse mathematical analysis.

This paper introduces linear integrated circuit, integrated operational amplifier application circuit, positive and negative feedback circuit and low power DC voltage stabilizing circuit, as well as the working principle, analysis method and basic application of the above circuits.

In all kinds of circuits, the basic knowledge of electronic devices and circuits is introduced in considerable length, such as PN structure theory, crystal diode, triode, field effect transistor, integrated operational element, frequency characteristics of amplifier circuit, application of negative feedback in amplifier, power circuit and other basic knowledge.