Here's how it works and why you can't directly change the resistance:
* Thermistors: These are resistors whose resistance changes significantly with temperature. There are two main types:
* Negative Temperature Coefficient (NTC) Thermistors: Resistance decreases as temperature increases.
* Positive Temperature Coefficient (PTC) Thermistors: Resistance increases as temperature increases.
* The Mechanism: The resistance change is due to the material's physical properties changing with temperature. In NTC thermistors, the material's conductivity increases as it gets hotter. In PTC thermistors, the material's conductivity decreases as it gets hotter.
How to "Control" the Resistance:
You can only indirectly control the resistance of a thermistor by manipulating its temperature. Here are some ways:
* Heat it up: Applying heat (from a heat source, current flow through the thermistor itself, or the environment) will increase the temperature and cause the resistance to change according to the thermistor's characteristics.
* Cool it down: Cooling the thermistor (using a cooling source or a colder environment) will decrease the temperature and cause the resistance to change.
Important Considerations:
* Thermistor Characteristics: Each thermistor has a specific resistance-temperature relationship. This relationship is usually provided in a datasheet.
* Thermal Response Time: Thermistors take time to heat up or cool down. This time is called the thermal response time. It's important to consider this when using them for temperature sensing.
* Power Dissipation: Applying too much current to a thermistor can cause it to overheat and change its resistance permanently.
In summary: You can't directly adjust the resistance of a thermistor. The resistance is inherently linked to its temperature. You can only control the resistance indirectly by changing its temperature.
