Control Transformer, 50VA, 120VAC: Electronic Transformers: Amazon.com: Industrial & Scientific
50 VA Micro Transformer - 480V Input Voltage - 120V Output Voltage - - Amazon.com
24VAC 50VA Wall Transformer with PTC Fuse Compatible with All Versions of Doorbell,Nest, Ecobee, Sensi and Honeywell Thermostat,Water Solftener,Screw Terminal Output - - Amazon.com