That's a great exercise. The hard part is always that in chips you can pull stuff that is rather tricky discretely, for instance, a multi-emitter transistor. So you can't always do a 1:1 conversion but for a 555 it is still doable.

I saw this a while ago:

https://www.instructables.com/Designing-a-555-Timer-on-Discr...

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direwolf20 5 hours ago | parent [-]

Only because odd components aren't marketable. There used to be 4-terminal MOSFETs, they weren't sold after ICs became normal. Never heard of a multi emitter transistor being sold discretely but it's possible.

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squarefoot 2 hours ago | parent | next [-]

Dual gate mosfets were a godsend when building RF/IF mixers or preamps. Luckily I have a small stash as they're almost unobtanium and costly these days, but for most uses such as mixers and preamps they can be swapped with a pair or normal jfets in a cascode configuration like this one: https://i.stack.imgur.com/6Nyhg.gif

	▲	cbdevidal an hour ago \| parent \| next [-]
		Today I learned you can build an entire freaking CPU out of 555s lol https://hackaday.com/2011/08/05/building-a-computer-out-of-5...
	▲	jacquesm an hour ago \| parent \| prev [-]
		> Dual gate mosfets were a godsend when building RF/IF mixers or preamps. exactly :) BF901 FTW.

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jacquesm 4 hours ago | parent | prev [-]

I use dual gate FETs frequently for all kinds of tricks and they're super useful.

Is that what you had in mind?