How do NTC thermistors suppress surge current? 1

The NTC thermistor (Negative Temperature Coefficient Thermistor), or negative temperature coefficient thermistor, is a temperature-sensitive semiconductor component. Its characteristic is that as the temperature rises, the resistance decreases; conversely, when the temperature drops, the resistance increases. NTC thermistors are widely used in circuits for temperature control and measurement, as well as to suppress surge currents during power startup. Before explaining how NTC thermistors suppress surge currents, let's first understand what surge current is and why it needs to be suppressed.diode

Definition and Hazards of Surge Current

Inrush current refers to the transient surge of excessive current that flows through a circuit when an electronic device starts up or powers on. This current can far exceed the normal operating current levels of the device, potentially causing overheating, damage, or even burning out of electronic components, thereby shortening the device's lifespan. Therefore, it must be effectively controlled.diode

The working principle of NTC thermistors

NTC thermistors utilize their characteristic of decreasing resistance with rising temperature to suppress surge currents. During the initial startup or power-on moment of a circuit, the NTC thermistor's temperature is low, resulting in higher resistance that limits the current flowing through the circuit, thereby mitigating surge currents. As current flows, the NTC thermistor's temperature rises, causing its resistance to decrease, allowing the current to gradually increase to the normal operating level without damaging the circuit.diode