Physics Lab Equipment

LEEI-15 Apparatus of Measuring Liquid Conductivity

LEEI-15 Apparatus of Measuring Liquid Conductivity


  • Rich physical thoughts

  • Innovative experimental method

  • Ample hands-on training contents


LEEI-15, Apparatus of Measuring Liquid Conductivity, is designed with rich physical thoughts, innovative experimental method, and ample contents of training hands-on ability. It can be used for basic physics experiment as well as for scientific research of measuring liquid conductivity. 

The key device of the apparatus is a mutual inductive sensor with empty core for the measurement of liquid conductivity. It consists of two inductive coils which are wound on two high permeability iron-based alloy rings made of nano-materials respectively. The sensor uses a low frequency sine signal and the inductive electrode does not contact with the tested liquid, so no polarization is generated around the sensor. Based on this kind of sensor, the apparatus can measure liquid  conductivity with high accuracy. 

The LEEI-15 apparatus consists of an experimental signal source of frequency 2500 Hz, a sensor for conductivity measurement consisting of two inductive coils wound on two high permeability iron-based alloy rings, a set of high-precision resistances, a digital AC voltmeter, a 1000 ml measuring cup and connection wires. 

Using this apparatus, students can: 

1. Understand and demonstrate the working principle of the mutual inductive liquid conductivity sensor; acquire the relationship between the sensor output voltage and liquid conductivity; and understand the important physical concepts and laws such as Faraday's law of electromagnetic induction, Ohm's law and the principle of the transformer. 

2. Calibrate the mutual-inductive liquid conductivity sensor with precise standard resistors. 

3. Measure the conductivity of the saturated saline solution at room temperature. 

4. Acquire the relationship curve between the conductivity and temperature of the salt water solution (optional). 

The instruction manual contains experimental configurations, principles, step-by-step instructions, and examples of experiment results. Please click Experiment Theory and Contents to find more information about this apparatus.


Experiment power supply AC sine wave, 1.700 ~ 1.900 V, continuously adjustable, frequency 2500 Hz
Digital AC voltmeterrange 0 -1.999 V, resolution 0.001 V

mutual inductance consisting of two inductive coils wound on two high permeability iron-based alloy rings

Precision standard resistance

0.1 Ω and 0.9 Ω, each 9 pcs, accuracy 0.01%

Power consumption< 50 W

Parts List

Main electric unit1
Sensor assembly1 set
1000 mL measuring cup1
Connection wires8
Power cord1
Instruction manual1 (Electronic version)


Schematic of experiment wiring       LEEI-15-3.jpg

Relationship plot of Vout/Vin and 1/R       LEEI-15-4.jpg

Straight line fitting at linear region of above plot 

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