Transistors and diodes have (reverse) breakdown volatge ratings. What is not specified in datasheets are how long such voltages must be applied for breakdown to occur. Suppose a diode has reverse breakdown voltage of 100V. Will applying 100 V (appropriate bias) for duration of 1 ps, 1 ns, 1 us, 1ms or 1s cause breakdown ? How long breakdown voltages must be applied for breakdown to occur?

  • $\begingroup$ Also see engineering.stackexchange.com/q/23780/10902 $\endgroup$
    – Solar Mike
    Sep 16, 2018 at 13:29
  • $\begingroup$ Do you have a oscilloscope? Or do you have access to E-lab of your institute ? Always be a doer not only reader. The best way to find it out is pick up a diode general propose the one that @alphezero mentioned, then see on scope what happens, you can record the data in excel afterwards. The 1N4148 undergoes the avalanche breakdown about -75 volts, then try at least 10 other diodes and then build a Gaussian curve, it's amazing how much you can do with those data. $\endgroup$
    – user14407
    Sep 16, 2018 at 18:49
  • $\begingroup$ @SamFarjamirad I wish I had access to some lab/institute. But I am not an engineer, and asking this question out of interest. $\endgroup$
    – qazxsw
    Sep 17, 2018 at 4:35
  • $\begingroup$ Then i recommend you to review the very basics of circuit electronics and electromagnetism on University Physics of Young and Freedman, then if you interested more you can read The art of Electronics of Horowitz, i still use this book as a reference but great book to read cover to cover, it gives you an insight into electronics and it's mostly practical rather than a pure boring theoretical book. $\endgroup$
    – user14407
    Sep 17, 2018 at 7:24

1 Answer 1


Some data sheets are more comprehensive than others. The better ones will show this information if it is relevant.

Taking the very common 1N4148 diode for example, this data sheet from Fairchild gives

  • For the maximum repetitive reverse voltage,it doesn't give a duration, but note the word "repetitive", which means the duration of a single pulse is irrelevant.

  • For the non-repetitive peak forward surge current, the duration is specified, and different currents are specified for two durations, 1 microsecond and 1 second.

  • For the reverse breakdown voltage, the test conditions are again specified - a non-repetitive square pulse of length 8.3 milliseconds, and two different levels of breakdown current.

On the other hand, the data sheet for a far eastern clone might not be so explicit!


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