| Electronics > Beginners |
| Zener's burning out |
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| lordvader88:
I was using a 5V1 1/4W (surely it's not 1/8W?) in a linear PSU I made, and it would pass up to 20mA sometimes, maybe even 30mA. LTSpice said it would barely pass 1mA, and that was at 120Hz peaks. So I tried a 2v0 and 3v0, and they burned out too, during a test of about 15V at 300mA of the PSU. So now I have a 1/2W 5V1, if thtis burns out, I'll try a TL431. The schematic used a 1/2W zener, and I guess it will get pretty hot. 1W zeners and expensive I guess there's no question here, I'll try and see if 1/2W zener survives. |
| Vgkid:
Schematic, what value of current limiting resistor are you using? |
| james_s:
Without posting the schematic, how can you expect anyone to help you? |
| MagicSmoker:
Well, 20mA through a 5.1V zener works out to around 0.1W of Pd, so if a 0.25W zener is failing then either the current measurement is in error or the zener isn't actually capable of dissipating even 0.1W... If you bought said zener from some shady ebay seller for really cheap then no prizes for guessing which cause is more likely. That said, post a schematic and/or LTSpice .asc file if you actually want some help. |
| tggzzz:
--- Quote from: james_s on July 19, 2019, 04:14:13 pm ---Without posting the schematic, how can you expect anyone to help you? --- End quote --- I refer you to a thread started by the OP yesterday - which was locked 4 hours later. https://www.eevblog.com/forum/chat/is-science-allowed-on-eevblog-if-it-contradicts-the-offical-version/msg2554770/#msg2554770 Currently he's at 911(!) posts. I wonder whether he will reach 1000. |
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