Supporting assembly

A supporting assembly comprising:

• a base comprising a main body and a first connection member, the first connection member being made of magnetic material, the first connection member protruding from the main body and defining a first hole;
• a rotatable member comprising a supporting member and a first shaft, the first shaft protruding from the supporting member and passing through the first hole, allowing the rotatable member to be rotatably coupled to the base;
• an electromagnet arranged on the supporting member and adjacent to the first shaft;
• and
• a switch electrically coupled between an external power supply and the electromagnet, and establishing or cutting off electrical connection between the external power supply and the electromagnet when the switch is turned on or turned off;
• wherein a current flows from the external power supply to the electromagnet when the switch is turned on, the electromagnet attracts the first connection member due to the magnetic force of the electromagnet, thereby fixing the position of the rotatable member relative to the base;
• and
• wherein the magnetic force of the electromagnet is turned off when the switch is turned off, whereby the rotatable member is capable of being rotated to a desired position relative to the base.