[Diy_efi] 555 timer for injector driver

[dh at busb.com]

If the MOSFET is saturated time off or time on should not contribute to
heat, only the number of transitions per second.  I sounds like your MOSFET
is not saturated.  You need a logic MOSFET which will be saturated by a
lower voltage on the gate.

dh


----- Original Message ----- 
From: "Daniel R. Nicoson" <A6intruder at myo-p.com>
To: <diy_efi at diy-efi.org>
Sent: Thursday, July 07, 2005 11:02 AM
Subject: RE: [Diy_efi] 555 timer for injector driver


> Jeff,
>
> I'd skip the solenoid to run your injector.  You're trying to control a
slow
> device (injector) with possibly an even slower device (solenoid).
>
> Use either a Darlington transistor or a Mosfet as has already been
> suggested.  They are not too expensive from the local Radio Shack.  I use
a
> good heat sink on the TIP-120 shown in the diagram.  When running at long
> pulse widths, it can build some heat.  (TIP-120 was used simply because it
> was in my parts bin, other Darlington's will work.  You would want to add
> few other things to use the Mosfet properly)
>
> I've attached a .pdf of the signal generator I've developed for use with
my
> projects.  Use as much or as little of this circuit as you wish.  I'm only
> using a breadboard version at this point. I may make up a PCB later this
> month.
>
> Take care,
>
> Dan Nicoson
>
>
> > -----Original Message-----
> > From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
> > Behalf Of jeff matthews
> > Sent: Wednesday, July 06, 2005 9:39 PM
> > To: diy_efi at diy-efi.org
> > Subject: [Diy_efi] 555 timer for injector driver
> >
> >
> > Hi-
> > To keep my ??? simple,  I built a 555 timer to work on a little
> > experiment,
> > I have it energizing the solenoid on a  12v relay, why won't it open and
> > close my injector? (it's just a basic saturated 550cc).  Is there some
> > secret to on making an injector operate?
> >
> > Like I stated,  this is for an experiment, just thought I could handle
> > making an injector fire on the bench...
> >
> > Best regards,
> > JEFF
> >
> >
> > _______________________________________________
> > Diy_efi mailing list
> > Diy_efi at diy-efi.org
> > http://lists.diy-efi.org/mailman/listinfo/diy_efi
> >
>


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