Timeline for 3mm LED reverse breakdown voltage
Current License: CC BY-SA 4.0
17 events
| when toggle format | what | by | license | comment | |
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| Dec 12, 2019 at 21:26 | comment | added | D.A.S. | Let us continue this discussion in chat. | |
| Dec 12, 2019 at 19:05 | comment | added | muyustan | @TonyStewartSunnyskyguyEE75 I was asking if it's possible to make Vbe = -5v or not. | |
| Dec 12, 2019 at 18:51 | comment | added | D.A.S. | read again. Vbe reverse = -5V max but if Vce = 100V that means Vbe<=0.7 while Vbc >= -99.3 | |
| Dec 12, 2019 at 18:47 | comment | added | muyustan | @TonyStewartSunnyskyguyEE75 hmmm, how one can apply more than Vbe(on) to a base emitter junction? Isn't it fixed at let's say 0.7 V? Maybe by grounding emitter and applying 10V to base? | |
| Dec 12, 2019 at 18:45 | comment | added | D.A.S. | the -5V is a property of physics for PN junctions when they are heaviliy doped junctions like LEDs. It is like a tiny weak Zener diode threshold that fails with low levels of power .. e.g. breakdown voltage of Vce can be used as a weak high voltage zener, but not recommended for Vbe or LED in reverse as the junction capacitance breakdown effects may be more destructive | |
| Dec 12, 2019 at 18:41 | history | edited | D.A.S. | CC BY-SA 4.0 |
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| Dec 12, 2019 at 18:38 | comment | added | muyustan | @TonyStewartSunnyskyguyEE75 yes, this is better. Thanks again. | |
| Dec 12, 2019 at 18:38 | comment | added | D.A.S. | Perhaps I was not clear. IF you drive an LED in reverse , expect a shorter life. How much depends on uA current. which is rated at -5V... for NPN the PN base emitter reverse = -5V while the PN jcn. Vce = Vbc reverse + Vbe forward | |
| Dec 12, 2019 at 18:38 | comment | added | muyustan | by "reverse voltage rating for almost all npn/pnp's", do you mean base-emitter or collector-emitter junction? I assume collector-emitter. | |
| Dec 12, 2019 at 18:33 | comment | added | D.A.S. | Mean time between failures = is a measure of average life for any equipment or parts. LEDs initially were 50k hours or 50kh and now much higher due to process quality improvements. So exceeding any ABS MAX spec degrades lifetime . it may be slow or sudden | |
| Dec 12, 2019 at 18:31 | comment | added | muyustan | I googled, but it came to me a little bit overconfusing for the purposes of this question. | |
| Dec 12, 2019 at 18:31 | history | edited | D.A.S. | CC BY-SA 4.0 |
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| Dec 12, 2019 at 18:28 | comment | added | D.A.S. | If you can't google "MTBF" Your journey to master electronics will be slow. | |
| Dec 12, 2019 at 18:26 | comment | added | muyustan | well thanks for the answer, but now I have to ask what does that ">50kh MTBF" mean? | |
| Dec 12, 2019 at 18:26 | history | edited | D.A.S. | CC BY-SA 4.0 |
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| Dec 12, 2019 at 18:21 | vote | accept | muyustan | ||
| Dec 12, 2019 at 18:18 | history | answered | D.A.S. | CC BY-SA 4.0 |