Pulse doubler schematic

[Steve Ravet]

jdzura at csc.com wrote:

> Maybe the guy with the PIC should just take care of the issue. It would seem that
> the PIC would be a simple circuit to build, and very easy to implement.
> What do you guys think?
> Joe D

A PIC seems like overkill, but I'm inclined to agree with it anyway.  It
would only be one part (not counting power supply parts), plus a jumper
to select double or half.

I think I like Bruce's original idea the best, though.  Two 555s, each
in monostable mode, one on the positive edge and one on the negative. 
That's one IC (556) plus some passive components, plus a couple
transistors to combine the outputs.  Battery voltage works fine.  It
also avoids programming the PIC.  You won't get a 50% duty cycle at all
speeds, but it doesn't sound like that's a problem since the ECM uses a
zero crossing detector.

--steve

-- 
Steve Ravet
steve.ravet at arm.com
Advanced Risc Machines, Inc.
www.arm.com