On Thu, 2005-06-23 at 21:12 +0200, Wouter van Ooijen wrote:
> > s/1N4148/BAT42/   12.9V -> 14.0V   :-)
> > 
> > In other words....  I took out the 1N4148s in my charge pump, and put
> > BAT42 Schottky diodes in their place.  The output voltage has gone up
> > from 12.9V to 14.0V 
> 
> I think you should not compare the open (unloaded) voltages but with a
> reasonable load (10..50 kohm). I dunno whether that will show a
> different picture, probably not.

With the schottky diodes I'm getting 13.3V with a 22 k ohm load
resistor.   I think your 2 pump circuit with silicon diodes should
theoretically give 3 x 5.0  - 3 x 0.6 = 13.2V off load.

A BAT42 reads 0.26V Vf on my test meter compared with 0.6V for the
1N4148, so the theoretical output should be 3 x 5.0 - 4 x 0.26 = 13.96V,
which is within experimental error.

So I think I'm "close enough for jazz"  ;-)  What say you ?

Plus it programmed a 16F828A with the extra load on.

Peter.


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