Curious if I can reuse an existing transformer for a doorbell system as the 9v reference (with the correct resistor to adjust)?
The doorbell would still be in use. Trying to understand if the reference needs to be fully independent or if there is some other reason not to do this.
Yeah, your indicated power utilization would change every time someone rang the bell. The bell transformer is also uncharacterized, so accuracy even when someone wasn’t ringing the bell probably wouldn’t be very good.