Abstract: For properly orienting, or setting in a predetermined angular position, a semiconductor wafer on a table on which integrated circuits or the like produced within and upon the wafer are tested with probes, the wafer is buoyed up from the table by a gas under pressure applied thereto from openings formed in the table and is further revolved substantially about its own axis, also by the application of the gas under pressure from a nozzle disposed above the table. A plurality of LED-phototransistor combinations sense the wafer orientation from the angular position of an orientation recess formed in the wafer, causing closure of solenoid valves to terminate the application of the gas under pressure when the wafer is properly oriented on the table. In another embodiment, the wafer is buoyed up and revolved by the gas under pressure emitted only from openings in the table.