Trying to determine if a diode UF5** (UF5 is all I can see, anything else is not visible ) is operable using only a Volt/Ohm meter. Is there a minimum voltage necessary to get a valid Ohm reading. This looks like a fairly robust diode and I get very high resistance in either direction with my ohm meter. Is it possible that I need a minimum voltage which my ohm meter is not providing for a valid test, or is this diode "dead"?