How to judge the stand or fall of diode

Diode of use number avometer archives, red watch the pen inserts V Ω Kong Hei to express a pen to insert COM aperture, we know pen of red in digital avometer watch contacts in-house batteries anode, black list pen contacts in-house batteries negative pole, and in avometer of pressing with a finger report is held back is red watch the pen contacts in-house batteries negative pole black list pen contacts in-house batteries anode, digital avometer red watch pen contacts diode anode, black list pen contacts diode negative pole, (measure to resistance) normal numerical value is 300-600 Ω to contact red watch pen diode negative pole next, anode of diode of the black contact that express a pen (measure retrorse resistance) , normal numerical value is ” 1 ” , if be measured twice,show 001 or 000 and buzzer is noisy, show diode already puncture, if measure positive and negative twice to all be to resistance ” 1 ” demonstrative diode open a way, if measure numeric close twice, explain pipe quality is very poor, retrorse resistance must is ” 1 ” or 1000 above, must be 300-600 Ω to resistance. Be diode is good.
      Diode: According to diode guide is connected, the principle that direction ends, with red watch pen and black list pen measure his to be being mixed to resistor retrorse resistor, if a group of data are measured so that be infinity or block value is greater, value of another group of block is lesser, state diode is normal.