Product Description
MZ5 series PTC thermistors are used in all kinds of fluorescent lamp electronic ballasts and electronic energy-saving lamps. There is no need to change the circuit and the product is directly connected to the two ends of the resonant capacitor of the lamp tube, which can change the electronic ballast and electronic energy-saving lamp. The hard start is the preheating start, and the preheating time of the filament is 0.4~2 seconds, which can extend the life of the lamp more than 4 times.
Specification
Product Name: MZ5 PTC Thermistor
R25 : 250-300Ω±20%
Diameter : 5mm
Non-action current : 75℃
Max voltage : 265V
Application : Electronic ballasts, energy-saving lamps
Color : Green or Yellow
Features
Excellent Positive Temperature Coefficient: At room temperature, a PTC exhibits a low resistance, allowing current to flow smoothly. When the temperature exceeds its Curie point, its resistance increases dramatically by several orders of magnitude, effectively limiting the current and exhibiting a "switching" characteristic.
Automatic Preheating and Protection: When a CFL starts, the PTC provides a low-temperature preheating current to the filament, allowing the cathode filament to emit sufficient electrons. Once preheating is complete, its self-heating causes a sharp increase in resistance, automatically shutting off the preheating current. The high voltage trigger then ignites the lamp. This process perfectly replaces traditional starters.
High Reliability and Long Life: As a solid-state ceramic component, the PTC has no mechanical contacts or moving parts, eliminating wear, adhesion, or arcing. Its service life far exceeds that of the lamp itself, ensuring exceptional reliability.
High Safety: Its inherent self-recovery properties ensure it maintains a high-resistance state after preheating, effectively preventing damage to the filament electrodes caused by repeated preheating and avoiding the "glow discharge" process, thereby protecting the lamp and core components such as the transistors in the ballast.
No Current Surge: Compared to traditional instantaneous start methods, the PTC preheat start method achieves a "soft start," eliminating current surges to the filament and significantly extending the lamp's lifespan.
Application
Electronic compact fluorescent lamps (CFLs): This is the most classic application. A PTC element is connected in parallel with an inductor to form a preheating and starting circuit. When power is applied, current primarily flows through the low-resistance PTC to preheat the filament. After 1-2 seconds, the PTC heats up and enters a high-resistance state, allowing current to flow through the inductor, generating a high-voltage pulse across the inductor to ignite the lamp.
Electronic ballasts for fluorescent lamps: Both integrated ballasts for compact fluorescent lamps and split electronic ballasts for linear/circular fluorescent lamps widely use PTCs as the standard preheating element to ensure compliance with International Electrotechnical Commission (IEC) preheating and starting standards, preventing premature blackening of the lamp ends.
HID lamp ballasts: PTCs are also used in ballasts for some high-intensity discharge lamps (such as metal halide and high-pressure sodium lamps) to provide auxiliary starting or protection.
LED drivers: In LED lighting, PTCs are also commonly used as overcurrent protection elements. When an abnormal overcurrent occurs in the circuit, the PTC heating resistance increases, thereby limiting the current and protecting the LED and driver power supply. When the fault is eliminated, the PTC cools down and returns to a low resistance state, and the circuit automatically resumes normal operation. It is a resettable "self-resetting fuse."
