I've just posted my fourth analog electronics design program to my web site. This one is for designing optimal Sallen-Key low-pass and high-pass filters (as opposed the the Multiple Feedback low-, high-, and band-pass filters designed by the program in the HP-67 EE Pac). Getting this program to fit into 224 steps proved to be challenging, but in the end, I shoehorned it in without compromising the functionality or usability I had intended for it.
The program and documentation can be found at http://www.stefanv.com/calculators/hp67_sallen_key.html.
If you haven't read my earlier HP-67 posts, I'm working on a sort-of-retro electronic project at the moment, so I decided I'd use my retro HP-67 to do all the design calculations. This is the last program I need for this project, so I probably won't post any more HP-67 programs soon.
I am however considering porting these to the HP-41C series (a fairly trivial endeavour), or possibly to the HP-35s. I wonder if there would be an interest in an HP-35s EE Pac (all as a single program with menus, like my Matrix Multi-Tool)?
Stefan Vorkoetter
Edited: 14 Dec 2008, 12:49 p.m.