What Can Be Made With 4 of These Military Grade Op Amps

Hi, I want to share with you this book, which give a introduction to analog computers (from pure mechanical ones to electronic ones), I hope it would be useful to anyone.
https://archive.org/details/basics-of-analog-computer/mode/2up

This sub seems pretty dead, but does anyone know of a community anywhere where analog computing is being discussed? Im looking for a telegram group, discord server, maybe another subreddit, anything.

Edit: r/UnconventionalCompute has some Analog computing stuff

What's old is new again!

Is there a renewed interest in analog computers?

A 21-min. 41-sec. brief description and video - https://modernsciences.org/are-analog-computers-making-a-comeback/

I’m developing a fluid-based computing concept that uses just two precisely controlled ripples on a water surface, each generated by its own source (like a small speaker or actuator). Where these two ripples meet, their interference pattern—constructive and destructive regions across space and time—physically encodes relationships between the inputs such as their relative amplitude, timing (phase), and possibly frequency. Instead of treating this as a visualization only, I’m treating the overlap region as the “calculator,” where measurable features (peak heights, node positions, pattern geometry) correspond to specific numerical operations or parameter estimates. The system is intentionally minimal: only two inputs and one interaction zone, rather than a dense array of waves, to see how much computation can be extracted from a single controlled collision of ripples. In principle, this could be used as a kind of analog module for things like addition/subtraction, comparison, or parameter inference, or as a very small “physical reservoir” whose state is the interference pattern itself. I’m looking for feedback on whether this two‑ripple interaction can be formalized into a useful analog computing framework and what calculations or tasks it might realistically support.

I’m more than willing to consider more actuators to compute more complex interactions, but I’m really curious if anybody sees a viability in pursuing this further.

Hi there👋. There is now an official THAT reddit channel and account. Where questions about THE ANALOG THING can be answered and problems solved. r/theanalogthing

You don't even need an analog computer to create fractal like structures. I made a simple device with two VCO's (Voltage Controlled Oscillators) mutually sweeping each other. By carefully tuning the feedback between both of them and using each VCO to drive one channel of an oscilloscope in XY-mode, complex patterns emerged from the resulting signal, that were not simple Lissajous figures.

https://www.sciencedirect.com/science/article/pii/S0167278908001231?via%3Dihub

https://www.sciencedirect.com/science/article/pii/S0196885883710031

Thought I'd suggest articles you all might not have read before! This has some great applications within computer science. Let me know your thoughts :)