Semiconductor device damage characteristics

Second, the damage of the triode is the PN junction breakdown or open circuit, in which the breakdown short circuit is mostly. In addition, there are two kinds of damage performance: First, the thermal stability is worse, the performance is normal at booting, soft breakdown occurs after working for a period of time; the other is that the characteristics of the PN junction are deteriorated, measured by a multimeter R×1k, Each PN junction is normal, but it can not work normally after being put on the machine. When measured with R×10 or R×1 low-range, it will find that the positive resistance of the PN junction is larger than the normal value.

Measuring the second and third transistors can be measured on the road with a pointer multimeter. The more accurate method is to set the multimeter to R×10 or R×1 (using R×10 files, and then using R×1 files when not obvious). , PN junction positive and negative resistance of the triode, the forward resistance is not too large (normal value), the reverse resistance is large enough (positive value), indicating that the PN junction is normal, and vice versa, it is doubtful, it needs to be measured after welding . This is the circuit's second and triode peripheral resistors are mostly in the hundreds, a few thousand ohms, using the multimeter low resistance value in the road measurement, you can basically ignore the influence of the peripheral resistance on the PN junction resistance.