This section starts with an ngspice example to walk you through the basic features of ngspice using its command line user interface. The operation of ngspice will be illustrated through several examples (Chapt. 20.1 to 20.7).

The first example uses the simple one-transistor amplifier circuit illustrated in Fig. 21.1. This circuit is constructed entirely with ngspice compatible devices and is used to introduce basic concepts, including:

Figure 21.1: Transistor Amplifier Simulation Example

• Invoking the simulator:
• Running simulations in different analysis modes
• Printing and plotting analog results
• Examining status, including execution time and memory usage
• Exiting the simulator

The remainder of the section (from Chapt. 21.2 onward) lists several circuits, which have been accompanying any ngspice distribution, and may be regarded as the `classical' SPICE circuits.