Simple injector Drive

[Bohdan L Bodnar]

The simplest solution (one I used in a fuel injector firing tool I recently
designed) is to use an enhancement mode N-channel MOSFET designed for
switching power supplies.  This thing can fire a high impedance injector (like
yours) practically forever without even warming up (and I'm NOT heat sinking
this transistor).  Be sure to stick a surge suppression diode across the
injector (NOT the transistor) -- I've measured voltage spikes in excess of 500
volts on high impedance Bosch injectors without surge suppressors.  I
reasonable surge suppressor will be a zener diode rated around 20-40 volts.

Cordially,

Bohdan Bodnar
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I have a question......

I want to (quick) flow test some injectors that I have.  I
will drive them with with a programmable function generator
(TTL out).  The injectors are the 16 ohm variety (GM).
What is the simplest circuit (FET, etc) that will take
the TTL and open the injector safely for a short test
and clean time.  I am not after a dissertation on the
subject, just something that will achive my goal.  I
have a few MC3484-S4 lying around - should I use one
of them, even though the MC3484-S4 is for lower-impedance
injectors?  

I know that something similar has been posted in the
past, however, I want the simplest solution (i.e.
quick to breadboard) that will get the job done and
not harm the injector.



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               Bruce A. Bowling
  Staff Scientist - Instrumentation and Controls
 The Continuous Electron Beam Accelerator Facility
    12000 Jefferson Ave - Newport News, VA 23602
                 (804) 249-7240
               bowling at cebaf.gov
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