555 EFI

[Clarence L.Snyder]

Bruce Plecan wrote:
> 
> -----Original Message-----
> From: Clarence L.Snyder <clare.snyder.on.ca at ibm.net>
> To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
> Date: Friday, January 15, 1999 11:57 PM
> Subject: Re: 555 EFI
> 
> >thergen at svn.net wrote:
> >>
> >> Bruce,
> >>
> >> Are you thinking of a string of one-shots and using a varying
> >> voltage on
> >> the control pins to vary the output pulse width?  If you're already going
> >> to be using op-amps to scale the output of the sensors, you could
> probably
> >> add/subtract the outputs of multiple op-amps together through resistors
> >> and run that into the control voltage pin of a smaller number of 555s.
> >>
> >question of clarification:
> >what is the "control voltage" pin? My understanding of the 555 operation
> >is the cap and resistance (cap between threshold {connected to discharge
> >for monostable}and ground - resistor from B+ to threshold) were an RC
> >"tank" circuit. The resistor controls the time required for the cap to
> >reach 2/3 of B+ voltage.
> 
> Pin 5 sets B+ as you discribe it.
> Bruce
> 
>
What do I connect to pin 5, through what, to control this? On the info I
have, this is the BYPASS pin and is tied to ground through a small cap
to despike. How do I use it to control pulse width? What degree of
adjustment is possible from this pin?

Another question -
What percentage pulse width change would be required from the MAP or TPS
input? What percentage from  engine temperature, assuming these were the
only inputs you were going to use other than the trigger (tach sync)?