The MF72 series 18D-13 is a directly heated, power-type negative temperature coefficient thermistor specifically designed to limit the inrush current during startup of electronic devices. Its core specifications include a rated zero-power resistance of 18Ω ± 20%, tested and calibrated at 25°C and 1.5VDC.
The material constant of 2800K ± 10% ensures stable performance over the entire temperature range. After power is applied, the residual resistance drops to 0.372Ω. It can carry a maximum steady-state current of 3A and is compatible with a capacitive load of 220μF for 240V systems or 820μF for 120V systems.
The thermal performance is demonstrated by a dissipation factor of 15mW/°C and a thermal time constant of 68s, which together produce a heat capacity specification of 1020mJ/°C, providing efficient surge suppression. The compact wafer has a diameter of 15.5mm and a thickness of 6mm. It is encapsulated in phenolic resin and features CP wire leads. It supports four mounting configurations: inward bend, outward bend, side bend, and straight lead.
It is mainly used for switching power supplies, UPS systems, display ballasts and heater equipment. Its operating temperature ranges from -40°C to 200°C, and its high reliability has been verified by 1000 3A on-off cycles.