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Voltage Level Switch

Supercap2F

Mar 22, 2014
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Dan Paulovich said:
What would I use for the U1 voltage regulator.

U1 is just the power connections for the comparator. :)

I'm going to power the circuit from a garden tractor, probably 13-15 vdc when running.

I thought you wanted to power it off of 12VDC.:confused: You will need a voltage regulator if you want to power it off of 13-15VDC.

Regards

Dan
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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This is what I meant:

divider.jpg

Sorry, R1 and R2 are labelled backwards as compared to your circuit.

Note that depending on the comparator (and especially if you're using an op-amp as a comparator), the input voltage range may not extend to the negative rail. In the case of the one shown above (the TLC3702) it does.
 

BobK

Jan 5, 2010
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And, once again, is the 12V regulated? If not you need a voltage reference.

Bob
 

Gryd3

Jun 25, 2014
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Having a regulated 12V source would allow this to be more stable... and would prevent the alarm from triggering on a false positive from the 12V source drifting. This of course will depend on what kind of accuracy the OP wants.

Alternatively, does anyone have any objections to using a diode on the + side of that Comparator?
+12V----\/\/\/\----+---->|----GND
You would need to feed the output from the Aneamoter to a voltage divider, but that would ensure a more stable reference voltage would it not?
 
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