Oil layer thickness meter - produces audio tone of frequency dependent on dielectric constant of medium through which probe passes

摘要

The cylindrical metal-clad probe consists of two electrodes in a Teflon (RTM) tip connected to a capactiance-to-voltage connector circuit. The probe output signal is amplified and fed to a voltage-controlled oscillator. The audio frequency output of the oscillator is fed via a volume control potentiometer and output amplifier to a loudspeaker or earphone. Two switches on the input amplifier may be used to set the sensitivity and tone frequency range. The probe is lowered into the tank or other liq. container on its scaled cable. As the probe tip passes from air to oil, the tone drops to a medium frequency, dropping to a lower frequency when the tip passes from the oil layer to the water underneath.