Abstract: A magnetic multi-pole propulsion array system is applied to at least one external cathode and includes a plurality of magnetic multi-pole thrusters connected adjacent to each other. Each magnetic multi-pole thruster includes a propellant provider, a discharge chamber, an anode and a plurality of magnetic components. The propellant provider outputs propellant. The discharge chamber is connected with the propellant provider to accommodate the propellant. The anode is disposed inside the discharge chamber to generate an electric field. The plurality of magnetic components is respectively disposed on several sides of the discharge chamber. One of the several sides of the discharge chamber of the magnetic multi-pole thruster is applied for one side of a discharge chamber of another magnetic multi-pole thruster.

Abstract: A circuit board includes a substrate having a through hole, a circuit layer, a first measurement mark and a second measurement mark. According to the first and second measurement marks, an electronic detection device can measure a first distance between a first edge of the through hole and the first measurement mark and a second distance between a second edge of the through hole and the second measurement mark to determine whether the through hole has an undesired size or shift.

Abstract: A circuit board includes a substrate, a first measurement mark and a second measurement mark, the first and second measurement marks are located on a predetermined punch area of the substrate. After punching, the predetermined punch area is removed such that the circuit board has a through hole and a sheet is separated from the circuit board. By the first and second measurement marks on the sheet, a first distance between a first edge of the sheet and the first measurement mark and a second distance between a second edge of the sheet and the second measurement mark can be measured to determine whether the through hole is shifted or has an incorrect size.