Abstract: A positioning device that has a support table, two pairs of sliding blocks slidably mounted in the support table, a positioning plate extending vertically at the top of each sliding block, a base on which the support table is supported, a cylinder in the base, a ball in the cylinder, a piston rod slidably mounted in the cylinder and pushing the ball to move upward in a vertical direction, so that the ball drives the two pairs of sliding blocks to move away from each other in the first horizontal direction and the second horizontal direction, respectively, until the positioning plates of the two pairs of sliding blocks abut against four inner walls of the opening of the circuit board, respectively, to allow the electronic device to be received in a positioning slot defined by the positioning plates, and a release mechanism that drives the piston rod to move downward in the vertical direction to allow the two pairs of sliding blocks to be moved toward each other in the first horizontal direction and the second

Abstract: A piezo film ultrasonic transducer has a piezo film including first and second opposing surfaces and a working portion and a lead-out portion. A first plated metal electrode layer is on the first surface of the working portion and the lead-out portion of the piezo film; a first conductive layer is on the first metal plated electrode layer; and a second metal electrode layer is on the opposite surface of the working portion and the lead-out portion. A first conductive layer is on the first metal electrode layer and a second conductive layer is on the second metal electrode layer.