#### Hanumantas

##### Newbie level 4

We have 3 basic analysis for a electronics circuits: DC Analysis, AC Analysis and Transient Analysis.

DC Analysis: Used to get the DC Operating point(Constant Voltage and Current) by making Capacitance OPEN and Inductance SHORT.

I have some confusion in AC Analysis, which is said to be small signal analysis by sweeping frequencies of the input signal.

For AC Analysis:

1. We first calculate the DC operating point by DC Analysis.

2. For small signal analysis, we assume linear behaviour near the DC Operating point. But in Simulator we can make input signal vary from 1mvolt to 100volts and we get the bode plot for that. But as we say small signal model is only valid for small signal which see the small part of Output Current/Input Voltage curve linear across DC operating point. Then why does we can be able to feed large signal of several volts in AC analysis.

I have this doubt of AC analysis with its concept of small signal analysis. Please do explain with respect to simulators LTspice or by concept..

Thanks in advance...