This method is connected to each detection point on the circuit board from a probe with a spring. The spring makes each probe with 100 -200g pressure to ensure that each detection point is well -touched. Such a probe is called "needle bed" together. Under the control of the detection software, the detection point and the detection signal can be programmed. Figure 14-3 is a typical needle bed tester structure. Detectors can know the information of all test points. In fact, only the probes of test points that need to be tested are installed. Although the needle bed test method may be detected at both sides of the circuit board at the same time. When designing the circuit board, all the detection points should still be on the welding surface of the circuit board. Needle tester equipment is expensive and difficult to repair. The needle selects different arrangements according to its specific application.

　　A basic general raster processor is composed of a drilling board with a pitch of 100, 75, or 50mil on the center of the pins. The function of the punch has the role of the probe, and uses the electric connector or node on the circuit board to perform a direct mechanical connection. If the pad on the circuit board matches the grid, then the polyphoric film according to the standardized punching vinegar will be placed between grid and circuit board to facilitate designing specific detection. Continuous detection is implemented by accessing the end point of the grid (X-Y coordinates defined as a pad). Since each network on the circuit board is performed continuously. In this way, an independent test is completed. However, the approximation of the probe limits the effectiveness of the needle bed test method.