Quote:
Originally posted by bigben2k
That would assume that the voltage difference is greater than 1.3v: if your supply is off by half of that, you had a problem to start with.
I'll let Yo_Duh complete the answer here, as I'm planning to switch off one of three supplies.
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That 1.3V number is the forward voltage of the zener with 78 Amps through it. The forward voltage will be substantially lower than 1.3V at lower currents.
My impression, was that part of the goal was to prevent current from flowing back into a PSU in the event of PSU failure or one of the PSU's not being turned on, as well as preventing one PSU from charging up another's output at powerup, due to differing startup times.
I still say the statement, "no possibility of the supplies attempting to charge each other", is false, unless some exceptions are listed.
Edit: punctuation