Max A capacitance bridge using a transformer would be a lot more stable than merely using the capacitance to vary the frequency of an LC oscillator.
The advantage of a capacitive sensing technique over a light beam is that it has much simpler and potentially more stable mechanical system than when a the mercury colum interrupts a light beam. Unless of course on has the Mercury column move a moire grating or similar setup such as making the top of the mercury column a reflector in an interferometer system. Bruce _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.