Electronics - Voltage and Current - Discussion

Thermistors are two types- ptc and ntc. Depending upon their operation they are varied in temperature co-efficient. so no need to confuse frndz :)))))

Thermistors are special solid temperature sensors that behave like temperature-sensitive electrical resistors. No surprise then that their name is a contraction of "thermal" and "resistor". There are basically two broad types, NTC-Negative Temperature Coefficient, used mostly in temperature sensing and PTC-Positive Temperature Coefficient, used mostly in electric current control.

Please say correct answer thermistor is PTC or NTC ?

A thermistor is a type of resistor whose resistance varies significantly with temperature

Assuming, as a first-order approximation, that the relationship between resistance and temperature is linear, then:

(Δ R)=k(Δ T),

where

ΔR = change in resistance
ΔT = change in temperature
k = first-order temperature coefficient of resistance

Thermistors can be classified into two types, depending on the sign of k. If k is positive, the resistance increases with increasing temperature, and the device is called a positive temperature coefficient (PTC) thermistor, or posistor. If k is negative, the resistance decreases with increasing temperature, and the device is called a negative temperature coefficient (NTC) thermistor.

Thermistor is a PTC resistor. Its ohmic value directly proportional to the temperature. Yogeshwari is correct only. Ravikumar answer only wrong.

If temperature increases then resistance value decreases means it is a negative temperature coefficient.

Thermal + resistance. Resistance of thermister varies with temperature having -ve temp coefficient.

Why photoconductive cell, potentiometer, rheostat are not temperature sensitive?

Here name it self specifies that thermistor is a temperature varing device.

Thermal+resister->thermistor.