= （thermal + resistor)
- PTC
- NTC
NTC 5D-15
An NTC thermistor is a temperature-dependent resistor whose resistance decreases as temperature increases.
Basic behavior
Temperature ↑ → Resistance ↓
Temperature ↓ → Resistance ↑
usage
1️⃣ Inrush current limiting (very common)
- Placed in series with AC input
- Cold → high resistance → limits surge current
- Heats up → resistance drops → normal operation
Typical applications:
- SMPS power supplies
- AC adapters
- LED drivers
- Motor controllers
connect
AC L ── NTC ── Bridge ── Bulk Capacitor
2️⃣ Temperature sensing
Used as a temperature sensor
Very sensitive, non-linear response
Used in:
- Battery packs
- Chargers
- Thermostats
- 3D printers
- HVAC systems