Abstract:
The management of water supplies on pastoral properties in the marginal rainfall areas of Australia is often hampered by the lack of an inexpensive reliable device for measuring the total salinity of ground water. The instrument described has been developed with this specific function in view although with further elaboration it could fulfil the requirements of an accurate laboratory, instrument for measuring conductivity. Basically the electronic components consist of an oscillator, a bridge, a single stage of amplification and a small speaker. When in use the speaker emits a high-pitched whistle until the bridge is balanced at a null point. By using transistors the current drain is low, the weight and cost of the instrument is Low and the equipment is rugged enough to withstand rough treatment. The total salinity of water can be measured accurately in terms of conductivity over the limited range covering the requirements for sheep and cattle and other ranges could be accommodated by minor modifications.