Table 7.

The test results of the fourth-level decision feature parameters about the diode characteristic voltage.

	the diode characteristic voltage from pin7 to pin8	the diode characteristic voltage from pin8 to pin7	Judgment result
Faulty circuit sample 1	1.66	2.22	abnormal
Faulty circuit sample 2	1.72	2.19	abnormal
Faulty circuit sample 3	1.77	1.83	abnormal
Faulty circuit sample 4	∞	∞	abnormal
Faulty circuit sample 5	1.42	1.42	normal
Faulty circuit sample 6	1.44	1.44	normal

The I–V characteristic curve between the pin7 and pin8 of the faulty circuit samples1-6 are examined by the transistor characteristic plotter, and it is observed that the characteristic curve between these two pins of the faulty circuit samples1-4 are abnormal, and the connection between these two pins of the faulty circuit sample4 is open circuit, as shown in Table 8.