Temperature characteristics of conductive rubber
01Conductive rubber
I. Introduction
This is a conductive rubber button that was removed from a game controller. At room temperature, the resistance in conductive rubber is about 100 ohms. But it will change with different pressures. Here two pins are used to contact the conductive rubber, and the corresponding resistance is about 120 ohms. Next, we are going to change its temperature by cooling the semiconductor, and qualitatively observe the relationship between the resistance of the conductive rubber and the temperature.
2. Test method
This is a semiconductor refrigeration chip placed on the heat sink. By applying voltages of different polarities, its surface can be heated or cooled, thus changing the temperature of the conductive rubber next to it. During this process, the contact between the metal tack and the conductive rubber is maintained without changing the relative distance. Observe the resistance between the two electrodes during this process. This is the resistance between the two electrodes when it is about 32 degrees outdoors.
3. Measurement results
Apply positive 12V to the semiconductor refrigeration chip, it can cool. The maximum operating current can reach 3.8A. If 12V is applied in reverse, it can cool. Use a multimeter to measure the change in resistance. During this process, the contact state between the metal probe and the conductive rubber remains unchanged. At this time, the resistance is about 100 ohms at room temperature. Positive 12V is applied below, and the semiconductor refrigeration chip starts cooling. During this process, because the hand touches the heating plate, the sample shakes, and the resistance value can be seen to change drastically. Next, change the voltage polarity so that the semiconductor refrigeration chip starts to heat. You can see that the resistance can go up to 145 ohms. Next, the voltage polarity is changed, the semiconductor begins to cool, the resistance begins to decrease again, and the resistance is finally less than 95 ohms. Through the above observations, it can be seen that the resistance of conductive rubber decreases as the temperature decreases and increases as the temperature increases.
Next, paste a thermocouple on the semiconductor refrigeration chip. This allows temperature and resistance to be displayed simultaneously. Let’s take a look at this measurement process again. This is a video sped up four times. You can see that the resistance increases as the temperature increases. When changing from room temperature to 100 degrees Celsius, the resistance increases by approximately 40%. ·This may be because temperature increases the distance between carbon particles inside the conductive rubber, causing an increase in resistance.
※ Summary ※
Through experimental research, this paper The higher the temperature, the greater the resistance. This is the same as ordinary resistors, which have a positive temperature coefficient. Judging from the resistance change range, normal temperature changes will not affect its use as a push button switch.
Temperature characteristics of conductive rubber