hall effect Junkyard link

Sandy sganz at wgn.net
Wed May 21 14:43:29 GMT 1997


I have used an IGBT, but not a mosfet. I would expect some of the same
problem with the IGBT, ie, a small ringing from the feedback circuit as it
was taylored for a darlington. The other problem is that most MOSFETs need
a higher gate voltage then what the LM1949 is supplying. You may be able to
use the Logic level Mosfets, but I havent messed with them. Best way is to
just plop one in and get a scope on the output. It is pretty easy to spot
the ringing or other glitches that way. One thing, why bother, a TIP121 is
about 75 Cents, and works very well!

Sandy

At 08:16 PM 5/20/97 -0700, you wrote:
>I am wondering if anyone out ther has put a 'scope on  the output from a 
>VW hall effect sender (in the distributor) and if so, could you inform me 
>waht to expect?  I am trying to get a distributor to test, but it would 
>be nice to get info before this weekend before I go pick one up?  Another 
>thing.  Has anyone used the National LM1949 with MOSFETs instead of the 
>suggested Darlington setup?  If so, does this change anything?  One more 
>thing.  I am really glad that I have the hel of 3 EETs for my staged 
>methanol injection project.  I think I might have completed it before 
>2000AD without their help, but I am not sure.
>
>Seth
>
>



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