Hi, I am building a little 70's style analog computer, mainly for learning purposes. For the most part I've been able to follow the Grappendorf project schematics, but that project does not include schematics for a comparator. I looked at the Anabrid THAT design schematics, and I was going to make something based off that; however, the Anabrid design uses Schmitt-Trigger inverters, which requires 5V supply, and I was hoping not to have to mess around with 5V, everything else in my system requiring only a +/- 15V. So, I was wondering if I maybe I could get rid of the Schmitt-Trigger inverters from the design and get by with just use op amps instead, like so:
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But when I try to build this, I've seen various strange results from the switches, like it getting stuck with seemingly one switch stuck open and one stuck close. I've done various bits of troubleshooting, but haven't got to the bottom of it yet. Is there something fundamentally wrong with the design? Maybe the Schmitt-Triggers are critical for some reason...? (Hysteresis?) I wonder if maybe I might have damaged the switches, so that might be it, but I can't afford to order more right now.