[Amps] B- questions

[Ron Youvan]

>  All conventional silicon diodes, of which the 6A10 is one,
> have a forward conduction voltage that starts at about .5 volts. The forward
> conduction voltage is not linear - applying additional voltage to it causes a
> "clamping" effect, while the current increases dramatically. Regardless of the
> amount of current passed, the voltage will not rise to more than about .7 volts,
> right up to the maximum current rating of the diode. I like the 6A10 because
> they are inexpensive and have a surge current rating of 400 amps, which should
> be enough for any ham application.

> If you can locate a graph of forward voltage vs current for a typical silicon
> diode, this should become more clear. 

   I don't see why hot carrier power diodes can't be used as Ammeter protection, I don't know how 
much they cost or if they are found at HAMfests.  The typical 35 Volt piV rating is irrelevant in 
this application.  The speed of a hot carrier power diode will surely surpass silicone.
   Adding a resistor in series with an Ammeter for protection should "recalibrate" it detrimentally, 
but when using a mil-Volt meter across a shunt, a series resistor could bring it into accuracy.
-- 
    Ron  KA4INM - Remember, the government cannot give anything to anyone
                   that they have not first taken away from someone else.  (like you and me)