On 2/6/06, Michael Rigby-Jones <Michael.Rigby-Jones@bookham.com> wrote:
>
>   Worse case the increase in current when the armature seperates could
> potnentialy cause the contacts to be closed again, which is obvioulsy not
> acceptable in some applications.



Wouldn't that be a violation of conservation of energy?
Current would have had to decay to the dropout point for the armature to
start moving, and then you're supposing that this motion results in enough
energy to stop that same motion (already 100% yield) and then reverse it?



> The 1N4148 is good for application up to many 10's (possibly 100's?) of
> MHz, is the rise time of the induced voltage really too fast? I guess that
> all depends on the speed of the driver but the commonly used saturated
> bipolar device is comparatively slow to switch off.


I've seen some pretty abysmal layout practices, where the diode's turn-on
would be extended quite a bit.
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