The Main Differences and Roles Between MOV and NTC

In power supply circuits, metal oxide varistors (MOV) and negative temperature coefficient thermistors (NTC) are commonly used for protecting other electronic components. Their roles are to ensure circuit safety, but they have significant differences. What are these differences and roles?

 

MOV (Metal Oxide Varistor)

 

MOV is primarily used for overvoltage protection. Overvoltage protection, also known as surge protection, is a method to disconnect the power supply or reduce the voltage of controlled devices when the voltage exceeds a predetermined maximum value. The MOV, such as the Kaeya HEL metal oxide varistor, is a nonlinear resistor component mainly composed of zinc oxide (ZnO). It has a very high surge current tolerance and nonlinear coefficient. Below its threshold voltage, its resistance is very high, allowing almost no current to pass through. If the threshold voltage is exceeded, its resistance drops sharply, allowing it to dissipate large currents. Due to this characteristic, as a protective component for electronic and electrical equipment, it plays a significant role in absorbing abnormal voltages and lightning surges. MOV varistors produced by UF Capacitors have advantages such as high current density, low limiting voltage, and good AC withstand capability.

UF Capacitors supply MOV with three grades MOV: Standard Series, Z-Series(High reliability), 6KV3KA Series for all meters.

 

NTC (Negative Temperature Coefficient thermistor)

 

NTC is mainly used to suppress surge currents. NTC thermistors are temperature-sensitive resistors made of materials with a negative temperature coefficient (NTC) and special semiconductor ceramics. They have a high resistance value at room temperature. When energized, their resistance decreases as their temperature rises due to self-heating. Utilizing this characteristic, they are used as current protection devices in electrical and electronic equipment, effectively limiting abnormal currents, including surge currents during operation.

 

NTC thermistors produced by UF Capacitors have extremely low resistance in operating conditions, consuming very low power in AC and DC circuits. They are particularly suitable for industrial applications such as motors, drivers, various power supplies, and processes like welding and plasma cutting.

 

In simple terms, MOVs are used for overvoltage protection, limiting surge voltages, while NTC thermistors are used for overcurrent protection, suppressing surge currents.

 

UF Capacitors MOV & NTC Cross Reference

For buyers, we have some cross reference to clearly show what UF Capacitors MOV & NTC can replace.

Details as below:

Leaded Varistor & Power NTC Thermistor
Photo	Description	UF Capacitors Series Code	Vishay SPRAGUE	Littelfuse	Panasonic	TDK/EPCOS	CNR	Thinking-TVR
	Metal Oxide Varistor Radial Leaded Varistor	VAR Series	VDR Series	LA Varistor Series ZA Varistor Series	ERZE**D***K Series ERZV**D***K Series	B722**S***K Series B722**Q***K Series	CNR**D***K Series CNR**V***K Series CNR**P***K Series	TVR Series TVR-V/TVR-D Series
	MF72 Power NTC Thermistor	NTC Series	***	***	***	B57 Series B57153S Series	***	SCK*** Series

 

 

 

 

 

 

 

 

 

 

 

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