Using an O2 sensor on a pos. ground car?

Is this possible?
The O2 sensor gives a small voltage that can be measured with a quality
voltmeter.
I'm no electronics guy, but I guess that voltage is with reference to
ground.  What happens when the ground is +12V?

The reason why I am not converting to neg. ground is that I am using a Crane
ignition for pos. ground.

Thanks,
    Ulix                                       __/__,__      ___/__|\__
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http://www.mirafiori.com/~ulix/               '67 Sprite     '74 X1/9