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Erin ๐Ÿ•ฏ @er1n
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happy circuit is producing happy waves
erin is happy, because it finally worked ๐Ÿ˜…

ยท Web ยท 2 ยท 19

you might wonder: why is Erin using a CMOS inverter for a saw VCO? the answer is abusing the nonlinear regions of the inverter to build a ramp generator and a Schmitt trigger that resets the ramp each cycle

it's scary that this works as well as it does

some rando came up with the idea by basically sticking an inverter wherever there was an opamp

schmitzbits.de/vco4069.html

@er1n eeeeeh...? i mean. an inverter literally is just a high gain op-amp, pretty much?

( like,... actually. especially once you're in weird deep-sub-threshold domains, but also everywhere else. CMOS is kind of a fuck, but that implementation idea also is pretty... motivated? i think? idk.

i'd be more informed about this but uhhhhh those classes where while i was abruptly crashing out of grad school. ๐Ÿคท )

@er1n I actually really miss the days (not that I was aware of them when they were here) where most things were 90% built out of 4000 or 7400 chips. I *love* the idea of a common set of parts being used in different devices - that you could raid a VCR to find spare parts for an alarm clock; that all appliances are basically Lego projects full of interchangeable and recombinable parts, and that no bit of silicon is single-use, permanently committed to one device which may break or go obsolete.

@er1n I remember reading about this when I went through my Lunetta phase.

There's not much you can't do with a sufficiently large pile of 4000 series chips, some ingenuity and a whole bunch of time.

@not_on_pizza @er1n

Based on the whole capacitor-resistor thing, I was going to guess some kind of oscillator... but hey, there it is, oscillating up on the oscillatoroscope.

<envies your oscillatoroscope; I only have a couple of old Tektronix 503 units that don't seem to work anymore>