No question, software can be expensivebut that is never an excuse not to pay for it. After all, someone (often a team) put a great deal of effort into writing that code. But when free software comes along, the "thrifty" among us usually take notice. It might just be a utility that can perform conversions or calculations that help speed a design.

Last month, for example, this newsletter introduced the MWI-2010 Microwave Impedance Calculator from Rogers Corp., an executable file capable of calculating transmission-line parameters for technologies such as microstrip and stripline based on a wide range of circuit-board laminates.

This week, semiconductor supplier Analog Devices and test specialist National Instruments have teamed on a free version of National's Multisim component evaluation tool (see story below). Sure, this is a limited version of the software, and it only works for components from Analog Devices. But this is a simplified version of a linear simulator, with more than 500 models. And those who know how to make the most of such software will quickly learn that some components from different manufacturers, such as opamps and switches, can be represented by similar models.

The results may not be exact, but they will provide a starting point for a design. Besides, who can argue with the price?