Re: schottky diode now another question!

DK
 

Hans,

Thank you for your prompt and very informative reply! 

I have another question, this time Peters DL6DSA’s LCD Contrast improvement modification. Peter writes:

"I have found a simple solution for improving the adjustability of the R47 contrast potentiometer in the QCX: By adding additional resistance between the grinder of the R47 and GND, 

The grinder? I don’t think we use this term ( as applied to a potentiometer; a sandwich but not a potentiometer )! 

Is the grinder the “wiper” often the center pin of the potentiometer? I really enjoy learning the differing terms we use for a common hobby. 

I have the 30  M kit which I will build as soon as I return stateside.

Thanks!

D.K. KD6TK 

On Dec 1, 2017, at 19:52, Hans Summers <hans.summers@...> wrote:

Hi Al

That is true, about the main reverse polarity protection diode. However he's not asking about that one, he's asking about the diode in this modification: http://qrp-labs.com/qcx/qcxmods.html#pwrup

73 Hans G0UPL

On Fri, Dec 1, 2017 at 3:48 PM, Al Holt <grovekid2@...> wrote:
It's the lower voltage drop. If a 'regular' silicon diode is used the drop across it is about .6V. The drop across the Schottky is more like .4V. This puts a slightly higher voltage on the PA FETs and a little more power out.


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