As temperature increases, what happens to the resistance of a PTC thermistor?

As temperature increases, what happens to the resistance of a PTC thermistor?

• A. Increases
• B. Decreases
• C. Remains the same
• D. Fluctuates

Answer: (A)

PTC stands for Positive Temperature Coefficient, so the resistance increases as temperature rises. In a PTC thermistor, heating causes a change in the material's conduction—often a phase transition in metal-oxide types that reduces charge-carrier mobility and dramatically raises resistance. As a result, the device starts with relatively lower resistance at cooler temperatures and becomes more resistive as it gets hotter. This is why the correct answer is that resistance increases with temperature; it behaves differently from (for example) NTC thermistors, which decrease in resistance as temperature goes up.

PTC stands for Positive Temperature Coefficient, so the resistance increases as temperature rises. In a PTC thermistor, heating causes a change in the material's conduction—often a phase transition in metal-oxide types that reduces charge-carrier mobility and dramatically raises resistance. As a result, the device starts with relatively lower resistance at cooler temperatures and becomes more resistive as it gets hotter. This is why the correct answer is that resistance increases with temperature; it behaves differently from (for example) NTC thermistors, which decrease in resistance as temperature goes up.