Arduino Uno R4

A lot of things Arduino has been putting out recently feels like it might be too little for too late or way to high of a price.

What bothers me about this release is that they are re-using the Uno name for a product that doesn't feel at all like and Uno. I don't think they should have used the name Uno unless they were at least sticking with the AVR family and 5V compatibility, and maybe I'd go so far as to say sticking with the ATmega328.

On the sticking with a 328 side, I would have liked an Uno R4 that expanded power input supported to 24v, replaced the USB-B with USB-C, could be configured to either 3.3v or 5v (defaulting to 5v).

I think moving on to a newer AVR, such as 4808, would be good for an R4 ONLY if the majority of libraries targeting UNO would just work on it.

Personally, my favorite was the Leonardo. I have a small bin of boards in the Arduino Pro Micro form factor, except the end G/5v/TX/RX pins have been replaced with a USB connector, and the 328 was replaced with a 32u4, so they are programmed as if they were Leonardos.

When I was a beginner, I wish someone would have handed me proper surface-mount parts and accompanying breakout boards that would turn them into TH components suitable for a breadboard.

Gate protection zeners are much more common in the more modern, higher-performance parts. So if you are used to using dinosaurs, you might think they're rare. Also, manufacturers occasionally get sloppy about noting their existence; you really need to see an I_GSS spec to be sure. (And because, well, if you're concerned about gate leakage, that is the spec!)

The 2N7000 is significantly worse than other MOSFETs. I don't know if that's because it's older, because its fab process is worse or was worse at one time, because it's easy to get those TO-92 legs into trouble, or just because of the die's low C_iss, but it's one fragile little bastard. The 2N7002 seems to be much better!

> Unprotected MOSFETs have nothing to do with "old" or "new".

Yes, they do, because the 2N7000 is older (1986) than integrated gate protection devices! Anything you see with them isn't a "true" 2N7000, even if it might meet the JEDEC spec sheet (which is rather hard to turn up...). Modern versions might have protection or might not (check the letters at the end of the part number... and hope you've got the right era of datasheet... and hope you've got the original MPN and don't have to read the condensed markings on the parts themselves... oh and hope you know the actual manufacturer!), but if they're older then they certainly won't have protection. So it kind of is an old (nope) versus new (maybe) thing.

> You can't just replace unprotected MOSFETs with protected ones and hope that your circuits work. You very well could be shorting out some circuit inadvertently.

Okay, technically, yes. In practice, no. Enhancement MOSFETs are usually used for power/switching applications, which won't care one damn bit about a silly diode, or in feedback loops for analog applications, which again won't care much. For various reasons, JFETs and depletion MOSFETs are usually preferred in analog-land, along of course with ICs. That's not to say you don't see discrete enhancement MOSFETs, but it's very, very uncommon. (And when I try to design that sort of stuff, I always seem to get stuck on not being able to find a FET without the pesky diodes built in. Sigh.)