Recalling the relaxation oscillator basaed LED driver from a while back,

I was wondering if anyone can show me how to drive the toroid transformer
with an N-Channel JFET instead of the bipolar NPN.  The reason for this
is to overcome the .6V threshold voltage of the BE junction of a bipolar
transistor necessary to get the curcuit to oscillate. Conceivably, with an
FET it could run from LESS than .6V. I know enough to realize the the FET
cannot be dropped in in place of the bipolar, since the bipolar is
current driven and the FET is voltage driven the circuit would need to be
rearranged.

While, this does seem a bit of a stretch on the topic side of things,
my purpose is understanding and experimentation with low power systems
for future PIC based projects.  I am just trying to add techniques to
my "tool box" for future use.

One example comes to mind:  A PIC driven from a single .5V solar cell or even
a single 1.5v AAA, AAAA, or button cell.

Thanks!

Dan


*******************************
* Dan Larson                  *
* Software Engineer           *
* Micro Control Company       *
* email: dlarson@citilink.com *
*******************************