How to replace the transistor in application?

How to replace the transistor in application?

the principles that should be paid attention to when replacing transistors are as follows.A high limit parameter is used to replace the lower product body tube.Such as high back pressure instead of low back pressure,medium power instead of small power transistor.

good performance in place of poor performance transistors.For example,a transistor with a high B value instead of a low value ( due to the poor stability of the transistor value,the value can not be selected too high );10small instead of I big transistors and so on.When other parameters meet the requirements,the high frequency tube can replace the low frequency tube.General high frequency tube can not replace the switch tube. The method of replacing the transistor is as follows.To find out the cause of the damage to the transistor,check whether other components in the circuit cause damage to the transistor,or the transistor itself is naturally damaged,when the transistor itself is damaged,it is necessary to replace the new transistor.The polarity of the new transistor cannot be connected to the wrong one,otherwise,the circuit can not work normally,and the other is that it may damage the transistor.When replacing the transistor,the original model should still be selected.If there is no original model, also should choose the transistor with similar main parameters.When the high-power tube is replaced,the radiating fin should be added to ensure the good heat dissipation of the transistor.In addition,we should pay attention to the insulation gasket between the heat sink and the transistor.If there is a primer,the transistor is not installed or installed well,may burn out the transistor.

Determine whether the transistor is damaged.In the repair of various home appliances,the initial judgment whether the transistor is damaged,to disconnect the power,will think that the damaged transistor is welded from the line,and remember the row of three poles on the printed circuit board.