AC Plug In supplies also known as "Wall Warts", "Wall Adaptors", "Wall Supplies" or “Wall Transformer” have been the mainstay of the commercial equipment market for many years. AC output Plug In Supplies are generally in the 6V-24VAC output range and are widely used in Door Bells, Access Control, Fire/Burglary and Surveillance systems. The input Voltage is limited to either 115VAC or 220VAC. Connections are usually molded in screw terminals with a few having wire leads. AC Plug In Supplies are actually nothing more than a Transformer in a handy plastic case. An AC Plug In Supply is inherently "Unregulated" or Brute Force and will provide an approximate output dependant on the load. A unit rated 24VAC@1A could be as high as 27VAC or more with no load or 23VAC under an overload. Some limit the output current with an internal fuse. In the event of a short or heavy overload this INTERNAL fuse will open rendering the AC Plug In supply useless. An AC Wall Plug In Power Supply is limited to lower power such as under 40VA because of the transformer and capacitor weight stress on the wall outlet. To that extent, some have a bracket that is attached to the outlet cover plate. All carry safety certifications by the CE, UL, CSA, TUV or other listing companies.