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If the temperature of the surrounding medium increases, it will result in a/an _____ in the resistance of the thermistor and a/an _____ in the current.
increase; increase
decrease; increase
decrease; decrease
increase; decrease
decrease; increase
A thermistor is a type of semiconductor resistor whose resistance is highly dependent on temperature. For a Negative Temperature Coefficient (NTC) thermistor, an increase in surrounding temperature leads to a decrease in its resistance, which according to Ohm's law, results in an increase in current flow.
A thermistor is a type of semiconductor resistor whose resistance is highly dependent on temperature. For a Negative Temperature Coefficient (NTC) thermistor, an increase in surrounding temperature leads to a decrease in its resistance, which according to Ohm's law, results in an increase in current flow.
Think of a turnstile at a station; heat acts like a crowd of people pushing past the gate, making it 'loosen up' and letting more people (electrons) flow through simultaneously.
NTC: Negative Temperature Coefficient тЖТ Nearer Temperature, Cool-er (lower) resistance.
RTтАЛ=R0тАЛe╬▓(T1тАЛтИТT0тАЛ1тАЛ) тАФ Steinhart-Hart equation or B-parameter model for resistance change
I=RVтАЛ тАФ Ohm's Law governing current flow
In semiconductor materials, increasing temperature provides thermal energy that promotes more electrons from the valence band to the conduction band. This process increases the number of charge carriers available, effectively lowering the material's electrical resistance. Since current I=RVтАЛ, if the voltage V remains constant, a decrease in resistance R directly forces an increase in current I.
Most thermistors used in industry are NTC types.
Semiconductors have a negative temperature coefficient due to increased carrier density.
Metallic conductors typically exhibit a Positive Temperature Coefficient (PTC) where resistance increases with heat.
High sensitivity to small temperature changes
Fast response time
Compact size
Non-linear resistance-temperature characteristic
Limited temperature range compared to thermocouples
Digital thermometers
Automotive coolant temperature sensors
Standard NTC thermistors are composed of sintered metal oxides like Manganese, Nickel, or Cobalt.
Option A and D are incorrect as they imply a PTC behavior or incorrect Ohm's law application.
B is correct тАФ An NTC thermistor's resistance drops as temperature rises, which facilitates higher current flow through the circuit.
Always identify if the component is a conductor (PTC, resistance increases with T) or a semiconductor (NTC, resistance decreases with T) before solving circuit problems involving heat.
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