An electrical device includes a top module having a display panel for displaying image, a bottom module having a plurality of buttons for controlling the operation of the electrical device, a base fixed on the bottom module, a first pivot extended out of the base, a rotation pedestal pivotably installed on the first pivot, a second pivot installed on the rotation pedestal having a protruding member, the top module being pivotably installed on the second pivot, a slidable housing slidably installed on the rotation pedestal having a block for propping up the protruding member while the top module rotates a predetermined angle around the second pivot so as to keep the predetermined angle between the top module and the bottom module, and a trace formed on the base for allowing the slidable housing moving along the trace.