Bruce Partridge wrote:
> The voltage divider is a 59K and a 47K resistor running from the
> battery.

That is a total of 106Kohms, which will draw 57uA from the 6V battery.
Also, this presents a 26Kohm impedence to the PIC, which is a lot more than
the 10Kohm maximum recommended by Microchip.  You should reduce the voltage
divider resistors and find a way to switch it on for only a short time when
measuring the battery voltage.  A P channel FET would work fine, or even a
PNP transistor if accuracy isn't too critical but cost is.

> The pic is powered by a 6V battery which goes through a 4 V voltage
> regulator.  The regulator powers the PIC, an op amp, and an led.

Is there a reason the opamp needs to be powered from the regulated 4V
instead of directly from the battery 6V?

> and the
> third is the output from the regulator which is being used as VREF.

But the regulator output is also being used as the PIC Vdd, so what's the
point of using the Vref input?


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