11 Feb
2014
11 Feb
'14
5:35 p.m.
On Feb 11, 2014, at 12:17 PM, David Riley <fraveydank at gmail.com> wrote:
On Feb 11, 2014, at 9:49 AM, Vincent Slyngstad <vrs at msn.com> wrote:
...
I?m a bit puzzled by this ?low voltage drop? requirement. Yes, Schottky will do that,
though I didn?t think those were in common use back then. Or, for sufficiently old
designs, germanium diodes.
The D664, however, wants the forward drop as low
as possible. Some 1N914 and 1N4148 will fit the bill, but others won't. If you are
looking for a general purpose substitution (rather than a specific application), the
1N4154 should work well. (When I studied the issue, I didn't find any manufacturers
of 1N4154 which had high forward voltage drops.)
If you're looking for low forward voltage drops, you could also try a
Schottky diode, which also tend to be fairly fast. Some may be hard
to find in through-hole, but depending on how worried you are about
visual authenticity, you could wire up some surface-mount packages
either with actual wires or with a tiny PCB jig. From what I remember of long ago physics and EE, the
forward drop of a junction diode is a function of the material and does not change
significantly from device to device. So if you?re looking at a silicon junction diode (as
the 1N914 is), the forward drop should be pretty much the same for all of them.
paul