That doesn't make sense at all. Fail open means the method of it's use is still in use.

Say you have a door that has powered locks. You want it to fail "open" so that when the power goes out, it's still useable, and people can get out. That's the source of the term.

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bryanlarsen 11 hours ago | parent | next [-]

MIL-P-1629 from 1949 formally defines fail-open mechanical switches that release pressure on failure.

The concept goes back to a pressure cooker invented in 1679 by Papin.

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calvinmorrison 11 hours ago | parent [-]

contextual, as are air brakes 'failing closed'. However, I wonder how fast Papin made his spagbol with his pressure cooker

	▲	froh 2 hours ago \| parent [-]
		[dead]

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perching_aix 11 hours ago | parent | prev [-]

Assuming the guy is for real (the closest relation I have to EE is accidentally electrocuting myself at times), I'm pretty sure they're referring to circuits breaking open or remaining closed, hence the opposite meaning.

Took me a minute as well, cause indeed with a computer background, the meaning is completely the opposite. Just like in other security contexts (door locks).

	▲	nailer 8 hours ago \| parent [-]
		The ambiguity is a good reason to avoid the expression entirely.