A user is seeking a free circuit testing program that includes diodes for voltage measurement at specific points. Recommendations include SPICE-like freeware from chipmakers such as Linear Technologies and Texas Instruments, with Linear's simulator having no limit on the number of nodes. INTUSOFT offers a fully functional evaluation of its ICAPS Spice modeling software, limited to 20 components but allowing for sub-circuit grouping. The software features a graphical interface for displaying DC voltages and performing parametric sweeps. Overall, several options exist for circuit simulation, each with unique limitations and capabilities.