The 1101 A/1102 Accessory Power Supplies and 1103 TEKPROBE Power Supply provide external power to accessories and probes when the oscilloscope or other instrument does not have the capability to do so. The power supply units are similar in design and function. They can operate at either 115 VAC or 230 VAC nominal voltage. Optional power cords are available to provide compatibility with different power source connections. All power supplies have overload protection. Each unit has a power switch on the rear panel and a power indicator on the front panel. The primary difference between the power units is that their front panels are designed for use with different specific probes. The following information describes the features and applications for each power supply product.