I have a 3.3V Zener diode, brand new from a reputable source.
When I set my Fluke 101 multimeter to diode test mode, and put the black lead next to the dark bar on the diode and red on opposite side, the meter reads a voltage drop of about 0.689V. This would be the forward voltage of a "normal" diode.
When I reverse the leads, however, the reading does not match the expected reverse voltage. Instead my meter reads 1.746V. I tried also with a Fluke 87V which gave a slightly higher reading of about 2.2V, but still not the 3.3V that it should be.
Now obviously for most diodes, a multimeter will just read "OL" rather than finding the actual breakdown voltage (which could be quite high). Why in the case of a low-voltage zener do multimeters give wrong (and different to each other) readings of the reverse voltage?