Abstract: A circuit for causing an element to produce a substantially linear response to an input signal comprising an element for providing a response, a transistor oscillator circuit for providing an electrical output signal of variable amplitude to excite the element in response to the input signal, the transistor oscillator circuit normally causing the electrical output signal to vary non-linearly with respect to the input signal, and microprocessor means for correcting the non-linear relationship between the input signal and the electrical output signal to thereby cause the electrical output signal to vary substantially linearly with respect to the input signal when the input signal is applied to the microprocessor means.

Abstract: A vibrator assembly for mounting on the bottom wall of a tank including a three-part insulating support housing including an outer support housing portion in the form of a nut which is located underneath the wall, a cap and intermediate support housing portion which is mounted with the cap above the wall and with the intermediate support housing portion below the wall and which threadably receives the nut, an inner support housing portion which is held by the nut within the intermediate support housing portion, with the inner support housing portion being part of a subassembly which includes a rubber vibrator support and electrodes and a vibrator and a rubber sealing insert all held within the inner support housing portion of the insulating support support housing and sealed therein by the tightening of the nut onto the intermediate support housing portion.