Fisher Impulse

[mollax]

Where this is connected?

[6666]

Does anybody have a slightly better resolution copy of this ?
thanks

[Aziz]

Does anybody have a slightly better resolution copy of this ?
thanks

http://www.geotech1.com/forums/showt...0572#post80572

Just zoom-in.

[6666]

Thanks Aziz
much appreciated for link.

And thanks Dave.

[Dave J.]

The Impulse was a commercial product, not a do it yourself hobby project. It's possible to strip the design down to about half of what you see here and still have a fun little PI. I'll leave the details to others, sorry, I don't have time to mess around with a hobby project.

In my experience this basic topology is a very forgiving design, back in the 1980's I built many variants of it. You can do almost anything to it, and if what you do isn't really stupid, it'll probably still work. So don't be afraid to play around with it, this isn't one of those projects where everything has to be "just right" to work.

--Dave J.

[6666]

I have tried some crude experiments with driving Q1 and Q2 with a 555
useing two separate TX and RX coils, no damping,
am getting a signal on RX coil, will try and clean it up
over next couple of days, the "current node" idea works a little bit different
as to how I thought it would work, interesting.

[6666]

In my crude experiment with the CRO across a coil of 250uH NO DAMPING
I am getting this wave form but I think only one tranny is switching with drive from 555
I can see a EMF from the coil with my gauss meter

[ODM]

Would be interesting to hear what was the Fisher Impulse's coil spec. Was the coil split into two sets of windings (inner/outer) and was it shielded? I remember reading it being a split winding coil, but I don't remember if it was shielded or not.

[Altra]

Look at post #1 in this thread there is a schematic showing the coil wiring. It appears to be shielded.

[FatBob]

I'd love to make one of these but haven't seen any board designs.

Is the coil center tapped or like a dual field? I have a centertapped 300uh coil I wound up a while ago...

[WM6]

Regarding battery consumption Fisher Impulse is dream design for all nowadays PI designer.

Battery in Fisher Impulse last forever, in comparison to 2-hours work with some of modern PI creations.