AMWEI - Lighting Switching PTC Thermistor
From PTC Thermistor
Lighting Switching PTC Thermistor are used when a load in series with the PTC thermistor has to be switched off after a time delay and when switching occurs frequently. A typical application of switching PTC thermistor is the preheating of electrode in energy-saving lamps or fluorescent lamps. Switching PTC can also be used as a power resistor for loading a capacitor, for example in power supplies or in control units of production equipment.
Lighting Switching PTC thermistor Application
It's applicable to various types of fluorescent lamp, electronic ballast and electronic energy-saving lamp. The PTC can be connected across the lamp resonator without changing the circuits. It can change hard start of the ballast and electronic energy-saving lamp to preheated start and the preheating time of the filament can come up to 0.4-2 seconds, which will extend the service life of the fluorescent tube by over 4 times.
Switching PTC thermistor Operating Principle
The application of the PTC thermistor to achieve preheated start is as follows: Immediately after power is switched on, Rt is in normal temperature state and its resistance is far lower than the C2 resistance. The current through C1 and Rt forms a return circuit to preheat the filament. After about 0.4-2 seconds, Rt joule heat temperature exceeds Curie point Tsc and skips into high resistance state of far higher than C2 resistance. The current passes through C1 and C2 to form a return circuit, which causes L resonance and produces high voltage to light the fluorescent tube.