If you don't have an existing doorbell but would like to avoid the need to charge the battery of your Ring Video Doorbell (2nd Generation), you can directly connect your Ring Video Doorbell to a low voltage 8-24V AC transformer.
The Ring Video Doorbell (2nd Generation) can only be connected to an AC transformer or a Ring Plug-In Adapter (2nd Generation). The Ring Plug-In Adapter has been designed specifically for Ring Video Doorbells and has additional safety features not found in other DC supplies to ensure that you do not damage your Video Doorbell or power supply. Do not use any DC power supply not made by or certified by Ring.
A resistor is not required.
Do not install a diode, as the in-home chime functionality is now controlled via the Ring app.
Note: Installation must be carried out by a qualified electrician.