Hej Magnus An elegant way of achieving some degree of temperature compensation may be to use 3 coaxial electrodes surrounding the mercury column. One relatively long one used to couple the bridge drive signal to the mercury column and located between the other 2. The top electrode one being used to sense the position of the tip of the mercury column and the lower one as a temperature compensation element in the other side of the bridge. A phase sensitive detector with a suitable preamp could be used to detect a capacitive null. The phase sensitive detector output drives a PID or other temperature control 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.