Specification

Instructions For Use

1. Add 0.2% sodium chloride solution and an appropriate amount of 3% phenolphthalein ethanol solution, with the water surface exceeding the sample by more than 10mm;

2. Connect the power supply. （AC220V±10%）；

3 . Place the power switch in the “ON” position, and the indicator light will be red;

4 . Adjust the voltage coarse and fine adjustment knobs to the desired output voltage (usually 12 ± 2V);

5 . Constant current regulation: To prevent excessive heating, the short-circuit current should not exceed 500mA;

First, adjust the voltage to any value between 3-10V, set the current thickness knob to 0 and turn it counterclockwise to the end. Then, short-circuit the positive and negative terminals with a wire, adjust the current thickness knob clockwise to the desired current value, and finally remove the short-circuit wire and adjust the voltage thickness knob to the desired voltage value.

6. Set the time relay to the desired time.

7. Heat the sample according to the regulations and cool it to room temperature without bending or stretching. Then connect one end of the sample to a black terminal (negative electrode) and place it in a solution tank (positive electrode). The other end of the sample should be exposed to the solution. Activate the “Test” button, and the buzzer will sound an alarm when the time is up. You can observe with normal vision, record the number of pinholes, and press the “Test” button again to reset to standby mode.

8. Attention! After completing the experiment, the saltwater should be drained and rinsed clean with clean water, otherwise the saltwater tank is easily corroded.

Preparation method of phenolphthalein sodium chloride solution:

The concentration of sodium chloride solution is 2g/L, and an appropriate amount of phenolphthalein ethanol solution indicator with a concentration of 30g/L is added to the solution. The solution should be fully dissolved. (A light red stream appears in the pinhole solution of the sample) – To ensure the accuracy and clarity of the test, fresh phenolphthalein sodium chloride solution should be prepared daily.