The ngspice simulator supports the following different types of analysis:

1. DC Analysis (Operating Point and DC Sweep)
2. AC Small-Signal Analysis
3. Transient Analysis
4. Pole-Zero Analysis
5. Small-Signal Distortion Analysis
6. Sensitivity Analysis
7. Noise Analysis

Applications that are exclusively analog can make use of all analysis modes with the exception of Code Model subsystem that do not implements Pole-Zero, Distortion, Sensitivity and Noise analyses. Event-driven applications that include digital and User-Defined Node types may make use of DC (operating point and DC sweep) and Transient only.

In order to understand the relationship between the different analyses and the two underlying simulation algorithms of ngspice, it is important to understand what is meant by each analysis type. This is detailed below.