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A couple years ago, I modified the voltage output of a DC power supply from 12 V to 6 V. I remember using this online calculator to get the proper output voltage (see picture):

screenshot

Image source: Circuit Easy - TL431 Voltage Calculator

Unfortunately that day I had a limited choice of resistors to pick from and the most suitable resistors values I could find were 700 kΩ and 900 kΩ. I soldered them onto the proper pads and successfully achieved a 6 V output.

20 minutes later I heard an explosion. The electrolytic capacitors exploded. I suspect my choice of high value resistors caused this, but to this day I do not fully understand why the caps exploded. Could anyone give me insight as to why this happened?

SamGibson
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vulubalulu balulu
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    That's impossible to answer as we don't know the original schematics, how you modified it, which electrolytic caps exploded and what was their function in the circuit. – Justme Jun 12 '23 at 05:12
  • vulubalulu balulu - Hi, Please remember the [site rule](/help/referencing) which requires that when a post includes content (e.g. text, image, photo etc.) copied or adapted from elsewhere, that copied content must be correctly referenced. As a minimum, the source webpage or PDF etc. should be linked (see that rule regarding references for books / articles etc.). In order to help you, I found what I believe to be the source webpage link & added it for you. For the future, please remember it's your responsibility to do that :) You can see the [tour] & [help] for the main rules. Thanks. – SamGibson Jun 12 '23 at 07:46
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    `700 kΩ and 900 kΩ [achieved] 6 V ` I find that odd, ignoring effects of excessive resistance, I'd expect 5.7 V (or 4.4 V). – greybeard Jun 12 '23 at 07:57

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