Can you use a plug in transformer with the Ring Pro Doorbell? Yes. What plug in transformer should you use that will be compatible with the Ring Pro Doorbell? We teach you how to install a new transformer for your Ring Pro Smart Doorbell if you don’t have any existing wiring and what plug in transformers will work with the Ring Pro Video Doorbell. We also provide a guide of everything you need to install a Ring Pro Doorbell if you are replacing an old battery powered doorbell or need to connect your doorbell to new power source. The Ring Pro Doorbell requires a constant supply of 16V-24V AC (Voltage) and 30VA(Amperage) to maintain a full power. It’s important to select the right doorbell transformer for your Ring Pro Doorbell for proper functionality of the smart doorbell.