Voltage Check
Clinton Peterson, 28th Civil Engineer Squadron industrial electronic control technician, connects the contact leads of a voltage meter to wires in a circuit box on Ellsworth Air Force Base, S.D., Dec. 22, 2011. If one of the circuits isn’t working properly, or if the temperature drops in a building, an alarm notifies the control shop to respond and fix the problem. (U.S. Air Force photo by Airman Alystria Maurer/Released)