Why did the lamp of electronic ballast turn on for a long time
Characteristics of the fluorescent lamp, lamp began to ignite need a high voltage, normal light allows only by small current, the voltage is lower than the voltage at the ends of the tube. Electric fluorescent starter switch role in the circuit, it consists of a neon tube and a capacitance in parallel, and the role of the capacitor to eliminate the power supply of electromagnetic interference with ballast tank formation, and increase the voltage amplitude of the start pulse. An electrode in the discharge tube with double metal, use neon bulb discharge heating, make the bimetallic strip when open and close, inductance ballast current mutation on both ends of the tube and generate high voltage pulse.
When the fluorescent lamp after access circuit, electric fluorescent starter began to glow discharge between two electrodes, the bimetallic strip heat expansion and contact with the static contact extremely, so the power supply, ballast, filament and electric fluorescent starter constitute a closed loop, current filament preheating, 1-3 seconds when the heating time, electric fluorescent starter of glow discharge between two electrodes, then the bimetallic strip cooling and static contact is extremely disconnected, when two electrodes disconnect instantly, the current in the circuit suddenly disappeared, so ballast produces a high voltage pulse, and it has to do with power superposition, on both ends of the tube and, make the inert gas ionization inside the tube caused by arc discharge, in the process of normal light, ballast self-induction is still stable circuit in current role.
On the working principle of inductance ballasts, fluorescent lamp and the current limit and the production of instantaneous high pressure equipment should call ballast, he is at the core of silicon steel ingot enameled wire, the iron core coil, the instantaneous power, can produce high voltage, self inductance on the electrodes at the ends of the tube (filament). This movement is alternating, when the regenerator (bubble) closes, the filament of the lamp passes through the ballast. When open the starter and ballast can produce high feeling on the ends of the tube filament, filament electron bombardment wall of fluorescent powder, repeated several times to break the starter, such movement will be repeated several times, to get through tubes. When lamp normal luminescence, smaller resistance, always keep open state, the starter of the electric current is stable through work lamp, ballast, lamp to normal light. Due to the ballast in fluorescent lamp work, there is always an electric current passes through, prone to vibration, and fever, so have a ballast of fluorescent lamp, especially the ballast quality is bad, will produce very big voice, use a long time, also easy to burn out.
This one, I feel that you basically do not understand the working principle of the ballast, I took a comparison of the core, you see. Working principle of electronic ballasts: 220 V electric rectifier dc, then filter under the wave, then the OTL oscillation circuit composed of two triode into high frequency ac and dc booster, get a + 300 V ac 1000 + V peak, about 30-80 KHZ high frequency high voltage to the tube ends, the light is on. (that is, when the voltage is turned down, the high frequency alternating current is formed through the oscillator circuit, and the fluorescent lamp is illuminated by the voltage of the transformer.)
