Fundamentals of Electronic Technology (III)__ Fundamentals of circuit analysis__ Basic amplifier operating principle

Amplifier is the basic unit circuit of various circuits . So-called “ Zoom in ”, Is the weak signal that will be input ( Voltage or current, etc ) To control the energy provided by DC power , And make the output change according to the change law of the input small signal .

So the essence of amplifier is energy converter .

1 working principle

For the convenience of analysis , We use capital letters and capital subscripts ( Such as 、、

)  Represents the DC component ; Use lowercase letters and lowercase subscripts ( Such as  、、  ) Represents AC component ; Use lower case letters and upper case subscripts to represent the total instantaneous quantity ( Such as 、、  )

When =0 when , The state of the amplifying circuit is called DC state or static working state , Referred to as static . At this time, there is a certain static working point on the input characteristic and output characteristic curve of the triode , We call it Q spot , It corresponds to a certain 、、、.

When an input AC signal is added to the amplification circuit , Such as

In this paper, the case symbols are too complicated , It's not over yet .