Conventional detection methods for fast recovery diodes

Conventional detection methods for fast recovery diodes

The multimeter can detect the unidirectional conductivity offast recovery diodes and ultrafast recovery diodes, as well as the presence or absence of internal open and short circuit faults, and can measure the forward voltage drop. If equipped with a megohmmeter, the reverse breakdown voltage can also be measured.

Example: Measure an ultrafast recovery diodes, the main parameters are: trr=35ns, IF=5A, IFSM=50A, VRM=700V. Set the multimeter to R×1 and read out that the forward resistance is 6.4Ω, n′=19.5 bars; The reverse resistance is infinity. Further obtain VF=0.03V/cubic×19.5=0.585V. Prove that the tube is good.

Notes:

1. Some single tubes, a total of three pins, the middle one is empty feet, generally cut off when leaving the factory, but there are also uncut.

2. If one of the tubes is damaged, it can be used as a single tube.

3. When the positive conduction voltage drop, R×1 gear must be used. If R×1k gear is used, the measured VF value will be significantly lower because the test current is too small, far lower than the normal working current of the tube. In the example above, if R×1k is selected, the forward resistance is equal to 2.2kΩ, where n′=9 tiles. The resulting VF value is only 0.27V, which is much lower than normal (0.6V).