[Diy_efi] 555 timer for injector driver

Michael Richards michael
Thu Jul 7 16:15:35 UTC 2005


Do not forget that you will need a flyback as well. Personally I find 
it's far easier to just buy one of those expensive national 
semiconductor injector driver chips and let it deal with the 
requirements. This way you're not limited to saturated injectors 
either. 

-Michael

> 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
>> 
>> 
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