Aaron Sawdey, Ph.D. on Nostr: I’m not really that kind of EE but I’ll say a shottky diode for D1 makes sense, I ...

I’m not really that kind of EE but I’ll say a shottky diode for D1 makes sense, I guess it’s just to improve the drive for a hi output, so low forward drop is good, you mostly get R1 and R2 in parallel as a pullup. The drop across D2 is going to set the base voltage of Q1 so you want it a little lower than Vbe for Q1 so the transistor is turned on hard. Doing the sim is probably the easiest way to see what all these forward drops are anyway.