An electronic device may include a power driver to receive power and to selectively provide power, and a plurality of power transfer contacts to receive power from the power driver and to provide power to an external device. A controller may control the power driver to provide power to the plurality of power transfer contacts based on a plurality of time periods having a frequency shifted such that a length of a second one of the time periods is different than a length of a first one of the time periods. The controller may control the power driver to disconnect power from the power driver to the power transfer contacts during a plurality of test time durations. The controller may obtain data during the plurality of test time durations.