Abstract: A salt analyzer is disclosed capable of measuring the conductivity of a saline solution when either contact or non-contact probes are used. In particular, the salt analyzer employs circuitry capable of switchably measuring the various electrical parameters necessary for determining the conductivity of a solution when either contact or non contact probes are used.

Abstract: A musical instrument tuning device for tuning a musical instrument, having a vibrating sound producing member, is herein disclosed. The musical instrument tuning device includes a tone sensor, connected to the vibrating sound producing member. A comparator is connected to the tone sensor. A signal generator is also connected to the tone sensor. A tone adjustor is connected to the comparator, and to the vibrating sound producing member. The tone sensor senses the rate of vibration of the vibrating sound producing element, and produces a tone sensor signal indicative of the rate of vibration. The signal generator produces a selected frequency signal. The comparator receives the tone sensor signal and selected frequency signal, and produces an error signal indicative of the difference between the tone sensor signal and selected frequency signal. The tone adjustor receives the error signal, and adjusts the rate of vibration of the vibrating sound producing element in response thereto.