What is self-heating effect in thermistor?

The self-heating effect is a phenomenon that takes place whenever there is current flowing through the thermistor. Since a thermistor is basically a resistor, it dissipates power in the form of heat when current flows through it. This heat is gener- ated in the thermistor core and affects measurement precision.

What is the supply voltage to an NTC thermistor?

5 volts
The source voltage Vs is 5 volts, the thermistor resistance Rt is 10K ohms at 25°C, and series resistor R0 is 10K ohms. Similar to the parallel resistor-thermistor combination above, this combination has maximum linearity around the mid point of the curve, which is at 25°C.

How do you stop a self-heating thermistor?

There are two things you can do to reduce self-heating: One is to use a higher-valued thermistor, e.g. 100K rather than 10K nominal — I’m not sure why 10K is the standard value, but it’s a poor choice in many applications. The other is to use a smaller reference voltage.

Do thermistors generate heat?

When a current flows through a thermistor, it will generate heat which will raise the temperature of the thermistor above that of its environment. If the thermistor is being used to measure the temperature of the environment, this self-heating effect will introduce an error if a correction is not made.

What causes NTC thermistor failure?

Usually, thermistor failure is caused by an open circuit due to mechanical separation between the resistor element and lead material. This can happen as a result of improper handling, thermal mismatch, or heat damage. Another common reason thermistors fail is simply aging.

How do you know if a thermistor is bad?

When a thermistor is failing, it’ll display incorrect temperatures, or you’ll see impossible temperature fluctuations. For example, you may initially get a reading of 210 degrees only to see the temperature drop to 189 degrees and jump back up again.

Why NTC thermistor is used over PTC?

The NTC thermistor provides variable resistance based on temperature. As temperature increases, the resistance drops from high to low and allows current to pass through. For an NTC thermistor, as temperature increases, resistance decreases. For a PTC thermistor as temperature increases, resistance increases.

Why do we use NTC thermistor?

NTC thermistors are used as ICLs (inrush current limiters) to protect circuits of electrical and electronic devices against inrush currents easily and effectively.