Angle adjustable device and electronic display unit using the same

An electronic display unit, comprising:

• a base having a fixing member disposed thereon, wherein the fixing member has a fixing surface, and a shaft is protruded from the fixing surface;
• a switch mechanism arranged in close to the fixing member, wherein the switch mechanism includes a locking ring, a first gear, and a second gear, wherein the locking ring has at least one block formed on the inner surface thereof, wherein the first gear is movably disposed on the shaft and has at least one contact incline formed in correspondence to the block, the contact incline having a first end and a second end, wherein the distance between the first end and the fixing surface is greater than the distance between the second end and the fixing surface, wherein the first gear is selectively engageable with the second gear;
• a rotator connected to the switch mechanism, wherein the rotator includes at least one connecting member connected to the second gear and a bracket;
• and
• an electronic device disposed on the bracket.