>>It may be possible to create this by using the propagation
>>delay of a logic gate(s). e.g. using an AND gate, simply
 ...
>The trouble is that he only needs the delay in the turn-on direction, it
>will need to turn off immediately.

Well the other problem is that gates provide delays of a few ns, so
you would need to string a LOT of them together to get up to
a microsecond.  But I suspect the RC delay as suggested is quite
good enough since the rise time of something like that is
fast enough not to be noise sensitive or require a schmitt-trigger
(though you could throw one in for good measure).

If that one-direction thing is true, that can be solved with
another gate (or with Alan's method, for minimum parts count).

Barry

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