Elsie 2.86 was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this software available.
This PC software was developed to work on Windows XP, Windows Vista, Windows 7, Windows 8, Windows 10 or Windows 11 and can function on 32-bit systems. The program lies within Education Tools, more precisely Science Tools. We recommend checking the downloaded files with any free antivirus. The program's installer file is generally known as elsie.exe. The actual developer of the program is James L. Tonne. The most popular versions of the Elsie 2.8, 2.5 and 2.4.
From the developer:
Elsie™ is an uncommon commercial-grade lumped-element ("L-C") electrical filter design and network analysis program, directed toward the engineer, technician or hobbyist involved in that line of work.
Elsie is 32-bit Windows® electrical filter design software nicely written to help engineers design and analyze lumped-element filters in the audio through microwave range.
You may want to check out more software, such as DeadLine, SRIM or Equation Wizard, which might be similar to Elsie.