Zener forward voltage drop

[markusw]

Most likely a stupid Q again, but I could not find it posted here.

Somewhere I read about Zener diodes having just around 0.3 V forward voltage drop. Compared to a 1N400x with around 0.6-0.7 V, one looses slightly less voltage when using it in series in a reverse polarity protecion. However, I bought some Zeners with reverse breakdown V of 15 (to be on the safe side with a 12V power supply) but all of them have an even higher V drop than the 4001s or even 4005s.

Does anybody know which kind of Zeners features a lower drop??

Thanks in advance.


Markus


Edit: Don´t know if it´s important, but the whole circuit draws around 15 mA. Not very zvexish   :wink:

[gez]

I think you're confusing them with 'Schottky' diodes

[markusw]

I think you're confusing them with 'Schottky' diodes

That´s what I just started thinking about!  

OK let´s rephrase the Q: what kind of Schottkys might I use. All the data sheets I checked so far give me around the same V drop as the Zener or the 4001. My Spice simulation says that with a BZX84C15L Zener and 15 mA through it there is a voltage drop of about 0.27V. When I look at the curves in the data sheets they give me a much higher forward V drop.  

:?:  :?:  :?:

[markusw]

Knowing what to search for makes it easier. I found a Schottky with around 0.4 V at 15 mA. (BAT 42)

Are there any Schottkys or Zeners with less?

[markusw]

I think I´ll go with R.G.´s MOSFET protection. Great: only 1m V voltage drop!