In this chapter we describe the parts available at the schematic level. Broadly speaking parts fall into two categories namely numbered and generic. Numbered parts, also referred to as model library parts are devices that have a manufacturer's part number and are described by a model either supplied with SIMetrix or by the manufacturer itself. Generic parts are devices that are defined by one or more parameters that are entered by the user after the part has been placed on the schematic.

A transistor like a 2N2222 or BC547 is an example of a numbered part and a resistor is probably the simplest example of a generic part.

There are some parts that have characteristics of both types. CMOS IC designers would use MOSFETs defined by a model but will then customise it with length and width parameters. Saturable inductors have an underlying model to describe the core's characteristics but a number of user defined parameters to define the geometry and air gap.

Numbered parts need a model which is usually stored in the model library. Refer to Device Library and Parts Management for details.

This chapter is concerned only with devices at the schematic level. Many of these devices are implemented directly by the simulator. For example the simulator has a bipolar transistor model built in and such devices can be defined with a set of simulator parameters. However, not all devices are implemented directly by the simulator. It does not, for example have an operational amplifier device built in. These parts are constructed from a number of other parts into a subcircuit.

The devices built in to the simulator are described in the "Simulator Devices" chapter of the Simulator Reference Manual.