expo/VCO equation questions

[Martin Czech]

I knew I had a gnuplot file for an expo converter with tempco.  It is
assumed that you use the usual npn expo converter, the npn in the
feedback loop has base to ground, the other gets the input voltage via
resistive devider.  If your circuit works the other way, simply change
the sign of the input voltage. Of course, ideal transistors are assumed.

The error is symmetrical arround 0V input voltage (if the tempco has
the right value). Therefore the middle module input voltage (key in the
middle) should lead to an actual input voltage of 0.0V. This way the
error is minimized over the keyboard.

The plot shows current, or current error.
Divide by C and delta_u and you have the (sawtooth) frequency.

m.c.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: temp_co.gnu
Type: application/octet-stream
Size: 926 bytes
Desc: temp_co.gnu
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/19990720/d2418c0b/attachment.obj>