Thanks for all the answers!
: )
73,
Rafael
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On 1/19/24 14:42, Evan Hand wrote:
On a search, I found that Zeners most often fail shorted rather than open on over current.? Since D3 is for protection, failing shorted would protect the devices taking power from the 5-volt rail from a voltage above the Zener voltage.? It would put a significant load on the regulator supplying the 5volts.? If D3 fails, I would suggest verifying the 5volt buck converter is working correctly, as that is what would most likely have had to supply the overvoltage to cause D3 to fail.
The 1/2-watt Zener should work as a sacrificial part on buck converter failure, provided a current limiting device is upstream of the regulator, like a fuse on the supply input.
73
Evan
AC9TU
