LIQUID-LEVEL SENSING PROBE AND CONTROL CIRCUIT

摘要

PURPOSE: To provide a method and a device for a liquid level sensor control circuit of a bioassay to control a position of a sampling probe to a surface of liquid in a vessel. CONSTITUTION: This is composed of a sampling probe 11, an oscillator circuit 33 joined to the sampling probe 11 to generate a first output signal having a constant frequency, a comparator 36 joined to the oscillator circuit 33 to generate a change signal when the first output signal changes to a reference amplitude by comparing the first output signal with a first reference amplitude and a control device 32 to control a position of the sampling probe 11 to a surface of liquid in response to the change signal.