For trade: 8 Mouser MOC3023S surface mount Optocouplers

[CaptKirk]

Wayne, that is very sound advice. However, doing something just because "it has always been done that way" when there may be a "better" way (and by better I mean a lot more common and a lot cheaper and potentially more reliable) then we should at least explore it. I am not trying to tell anyone else to do this, per se, just sort of doing the math because:

a) Schottkys have always bugged me. They are so darned hard to read the numbers on them!
b) I have a large qty of what I think is a substitute on hand for my work
c) The math is interesting and fun to think out as I like to "think different"
d) I'm cheap and do not want to stock all sorts of different diodes.
e) it is fun to try different ways to do the same thing and refine the process.

So, even if a 1N400x would be cheaper, and more readily available, please do not use them on your Renards!!

[ErnieHorning]

This is DIY, so there's nothing wrong with experimenting or poking around outside the box. Realize though, this is at your own risk.

One thing that you're leaving out is the tolerance. Even if you test it, there's tolerance's in all of the parts. It's common practice to design for 80% so if all tolerance's stack up in the worst direction, your circuit will still work.

[CaptKirk]

Mr. Horning, THAT is also good advice. This is just a thought experiment right now and a "just in case" for the future builds for me (I keep eyeing the pile of 1N4007 I have on hand). I was trying to use worst case numbers (low AC voltage at max current and minimum stated operational levels) to determine the tolerance (which sometimes is in short supply around here) in this situation.

So the conclusion is it is not recommended to use 1N400x but in a pinch, would likely work OK although at a reduced tolerance margin of the operation of the LDO voltage regulator.

[crazy_carpenter]

Update : trade is done so thanks for everybody's help. As far as substituting parts, this is my first board and kind of my proof of concept board so I think i'll stick with the plans. Playing around with my first Mouser order to replace out of stock parts is what got me in this mess in the first place ( I still can't figure out how I deleted the diodes and LED's LOL ). I finish this board and it is on to discovering the wonderful world of PIC programming and FM transmitters.