Salinity measuring system

A salinity measuring apparatus utilizes a specialized probe with dual electrode pairs, one of the pairs being used to pass current through the electrolyte, while the other picks up voltage drop across a region in the electrolyte and feeds it back to the current producing amplifier, which adjusts the current output until a stabilized, predetermined voltage difference occurs across the voltage electrodes. The circuit which drives the current between the current electrodes produces a positive pulse, and an ensuing negative pulse, which are sequentially applied across the electrodes so that two separate measurements are made using pulses of opposite polarity to cancel out electrode polarizations. An amplifier circuit receives a pulse from the voltage source and applies it to the electrodes. A second amplifier circuit picks up a voltage across a voltage dropping resister in series with the resistance of the electrolyte between the current electrodes, and amplifies this voltage drop for outputting to a signal register and processing means. A polarity reversal system is used at the output of the second amplifying circuit so that all of the processed pulses which output from the system have the same polarity despite the fact that internally in the apparatus the polarity is reversed. The pulse is transferred to the first amplifier circuit by a capacity charged transfer technique so that the system is electrically isolated from the pulse generator, and a second capacity transfer at the system output isolates the system from the output signal register and processing device.