🚀 go-pugleaf

In article <1jq3dlINNp2f@shelley.u.washington.edu>, whit@carson.u.washington.edu (John Whitmore) writes...
>In article <1993Jan21.101200.8651@mr.med.ge.com> szopinsk@picard.med.ge.com (Jerry Szopinski Mfg 4-6983) writes:
> 
>>The voltage drop across the 1N4148 diode depends on what type of
>>semiconductor material it is made of.  If the diode is made of
>>germanium (no, not the flowers) the drop is around 0.7V; if it
>>is made of silicon then the drop is around 0.5V.
> 
>	Nope; for Ge diodes 0.2-0.3V is typical.  Silicon is nominally
>0.6-0.7 (but this ignores resistance, which can drive either Si or
>Ge devices to 1V or more).  There are, for applications where this
>voltage drop is inconvenient, Schottky rectifiers that use Si and
>metal (Pt is typical) instead of N-Si and P-Si, and the forward
>voltage drop of these Schottky devices is usually considerably
>lower (0.3V or so).  Reverse holdoff voltages for Schottky diodes
>are usually modest (35V or so), which limits their application.
> 
>	LEDs are made of materials that have forward drops ranging
>from 1.2V (for IR) to 2.4V (the blue LEDs).
> 
>	John Whitmore

Since I started this thread I got a sizable number of responses (I haven't
sent any replies yet, since I am really busy - exams).  The idea of using
a Schottky diode has been mentioned several times so I am looking into
replacing the 1N4148 (which is too small, that's why I asked) with another
diode is rated at up to 1A and has an as small as possible forward voltage
drop as possible.  The max. reverse voltage is 5V so this should be no
problem, but I'd like to find a Schottky diode that has a max. reverse
current in the micro Ampere instead of mA range.
This diode is used on the TERMPWR (SCSI-bus) line to prevent an external
device from powering the computer (5-10A through the thin trace -> maybe 
copper vapor).
					Christian