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<p>This might be helpful if the battery being monitored is not also
powering the MPU. Just tie MPU ground to the top of the zener and
the zener input to the battery + terminal. The pot and meter are
not relevant. So "zero" is the zener voltage.<br>
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<p>Pete<br>
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<img moz-do-not-send="false"
src="cid:part1.Y2N1RTj9.8N3iB0hS@soper.us" alt="Zener circuit"
width="1073" height="1270">
<div class="moz-cite-prefix">On 8/16/23 16:28, The MacDougals via
TriEmbed wrote:<br>
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<p class="MsoNormal"><span style="font-size:14.0pt">I know how
to set up a voltage divider with a couple of resistors to
measure<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">battery
voltage of ~12v on an analog pin that accepts 3.3v.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">But, I
really am interested in a small segment of the range, say 9v
to 13v.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">How would I
“zoom” in on that range? I want to subtract/bias the vbat<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">by the 9v
minimum. So, 9v -> 0 and 13v -> 3.3.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">---> Paul<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
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