Using doorbell transformer as 9v ref?


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.


Is your transformer AC?

It needs to be an AC reference to get the phase info.

The details and calibration process are in the documentation

It should be fully independent. I don’t recommend using the bell transformer.

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.

Yes, the transformer is AC.

Makes sense, I will stick with the independent transformer.

Thanks for the information!