Abstract: The optical transducer is connected to a rotary shaft (71) for detecting the angular position thereof and generates corresponding electrical signals. The transducer comprises a casing formed by two casing halves (11, 12) which can be assembled together by means of latch elements (62, 63). Mounted on a first casing half (11) are three phototransistors (31, 32) for detecting the light emitted by a diode (58) mounted on the other casing half (12). A shutter disc (64) which is provided with radial openings is mounted rotatably within the casing on the shaft (71) which is supported by a self-aligning bush (19) which is mounted on a casing half. A flexible printed circuit (38) is disposed within the first casing half, parallel to the shutter disc and is in contact with the three phototransistors. The printed circuit has a projecting portion (43) which is bent over inside the casing so as to contact the diode (58) and a projecting portion (39) which extends out of the casing to be connected to an external connector.