In this case, the resistance of my thermistor is 100K Ohms, so my resistor is also 100K Ohms. The value of the resistor should be roughly equal to the resistance of your thermistor. Connect the CircuitĬonnect the thermistor and resistor to your Arduino like this: This equation can be rearranged and simplified to solve for R2, the resistance of the thermistor:įinally, the Steinhart-Hart equation is used to convert the resistance of the thermistor to a temperature reading. In terms of the voltage divider in a thermistor circuit, the variables in the equation above are: This is known as a voltage divider. The equation for a voltage divider is: The Arduino will measure the voltage at a point between the thermistor and a known resistor. However, the Arduino can’t measure resistance directly, it can only measure voltage. Since the thermistor is a variable resistor, we’ll need to measure the resistance before we can calculate the temperature. Let’s build a basic thermistor circuit to see how it works, so you can apply it to other projects later. In nickel oxide NTC thermistors, the charge carriers are electron holes. In NTC thermistors made from ferric oxide, electrons are the charge carriers. High temperatures cause the semiconducting material to release more charge carriers. The conducting material contains charge carriers that allow current to flow through it. NTC thermistors are made from a semiconducting material (such as a metal oxide or ceramic) that’s been heated and compressed to form a temperature sensitive conducting material. NTC thermistors are the most common, and that’s the type we’ll be using in this tutorial. In Positive Temperature Coefficient (PTC) thermistors, resistance increases with an increase in temperature. In Negative Temperature Coefficient (NTC) thermistors, resistance decreases with an increase in temperature. They are classified by the way their resistance responds to temperature changes. Thermistors are variable resistors that change their resistance with temperature. It includes all of the parts, wiring diagrams, code, and step-by-step instructions for 58 different robotics and internet of things projects that are super fun to build! How a Thermistor Works The 3-in-1 Smart Car and IOT Learning Kit from SunFounder has everything you need to learn how to master the Arduino.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |