What is the effect of fluorescent lamps?
Under the excitation of ultraviolet (uv), phosphor emit nearly white visible within the tube wall. Fluorescent lamp after normal glow. Due to the alternating current (ac) continuously through the ballast coil, the coil of self induction electromotive force, self inductance electromotive force blocking the current in the coil change, ballast step-down current-limiting role at this moment, the current stable in the range of the rated current of the lamp tube on both ends of the voltage is stable within the rated voltage range.
In polar disconnect moment, suddenly cut off the circuit current, ballasts have much self induction electromotive force, after the power supply voltage superimposition effect on both ends of the tube. The filament heat emitted when a large number of electronic, in under the action of high voltage on both ends of the tube, with great speed from low voltage end to the high electric potential terminal movement. In the process of accelerated motion, argon gas molecular collision tube, rapid ionization. Argon gas ionization heat, heat the mercury vapor, then mercury vapor were ionization, and the strong ultraviolet radiation.
The heat makes the bimetallic strip is heated in the process of inflation, because the degree of expansion of action contact, U still contact expansion elongation, contact with the static contact and processing circuit, the ballast poles of the contact. Touch the anode and the starter electric current through the ballast, on both ends of the filament form pathways. At this time, due to the closure between the starter, zero voltage between the poles, starter in the neon stop conductive, glow discharge disappeared, resulting in a decline in tube temperature and u-shaped contact cooling contraction, two contact plate separation, circuit automatically disconnect.
Working principle is: when the switch power supply voltage through the ballast and lamp filament immediately added to the poles of the starter. 220 v voltage immediately make the inert gas ionization of the starter, glow discharge is produced.
