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Thermistor (NTC)
An NTC thermistor is a temperature-sensitive resistor whose resistance decreases as temperature rises.
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Thermistor (NTC)
A thermistor can sense temperature.
For an NTC thermistor:
Hot → less resistance.
Cold → more resistance.
Recommended for Class 10
Thermistor (NTC)
A thermistor is a resistor whose resistance changes significantly with temperature.
An NTC thermistor has a negative temperature coefficient.
For an NTC thermistor:
temperature increases → resistance decreases
temperature decreases → resistance increases
Why It Happens
As temperature rises, more charge carriers become available in the semiconductor material, allowing current to pass more easily.
Applications
NTC thermistors are used in:
temperature sensors; thermostatic control; electronic thermometers; overheating detection; * temperature-compensation circuits.
LDR vs Thermistor
LDR responds mainly to light.
Thermistor responds mainly to temperature.
Thermistor (NTC) — Advanced
NTC thermistors are semiconductor devices with strongly nonlinear resistance-temperature characteristics. Thermal energy increases charge-carrier availability, reducing resistance.
Common Mistakes
Common Mistakes
- Mistake
Mistake: Applying the normal metal rule to an NTC thermistor. Correction: Do not apply the normal metal rule to an NTC thermistor.
- Mistake
Mistake: Hotter NTC has higher resistance. Correction: Hotter NTC thermistor → lower resistance.
Revision Zone
60-Second Revision
Quick cues from this topic — use them for last-minute revision.
NTC:
T ↑ → R ↓
T ↓ → R ↑
- Definition
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Practice
PQ
Q1. Define thermistor.
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Q2. Define NTC.
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Q3. State hot response.
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Q4. State cold response.
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Q5. Compare LDR.
Exam Practice
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Q1. Explain NTC thermistor.
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Q2. Describe temperature-resistance relationship.
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Q3. Give applications.
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Q4. Compare thermistor and LDR.
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Q5. Explain why NTC resistance decreases with temperature.
School-standard facts for Matric and Intermediate. Original explanations — not copied from textbooks.