TWI262745B - Preheating and activation controlling device of fluorescent lamp and method thereof - Google Patents

Abstract

A preheating and activation controlling device of fluorescent lamp and method thereof, which includes a preheating current detecting device, a preheating time determining device and a preheating time counting device. The preheating current detecting device is employed to measure a preheating current flowing through a filament of the fluorescent lamp and forward the preheating current to the preheating time determining device for determining a most suitable preheating time; eventually, the preheating time determining device issues a command to the preheating time counting device to the most suitable preheating time. The present invention can effectively solve the issue that a fluorescent lamp of conventional technique is insufficiently preheated, making it fail to be lighted up, and the issue that the fluorescent lamp is overheated to reduce the operational lifespan of the fluorescent lamp.

Description

1262745 IX. Description of the Invention: [Technical Field of the Invention] The present invention is a fluorescent lamp preheating and starting control device and method thereof, in particular, a kind of preheating current flowing through a filament of a fluorescent lamp. When determining the most suitable pre-=, the fluorescent tube will not have the problem of insufficient preheating to illuminate the fluorescent tube, nor will it occur in the technical field of preheating the fluorescent tube to reduce the life of the fluorescent tube. .曰 【Prior technology】

Since Edison's invention of the Incandescent Lamp in 1879, it has completely changed: the staff's workday, $, has also effectively extended people's masterpieces and entertainment time, enabling the industry and commerce to prosper. However, due to its low luminous efficiency and shortevity, the self-contained lamp has been gradually replaced by a fluorescent lamp (Flu〇rescent Lamp). Because fluorescent lamps have negative resistance, so the actual should be strong - stabilizer (job st) to limit the lamp power = and help the tube start. With the development of power electronics technology, there are various types: 1 type stability, which not only has high luminous efficiency, high power factor, no flash, and light weight, but also can extend the use of lamps. Life and dimming function [Reference] 5: However, electronic stability n, because of its high manufacturing cost and high price, so - can not be generally accepted by the market. The traditional inductive ballast (or electromagnetic ballast) has the disadvantages of low power factor of volume j and (4) service life, but its price is very cheap, which is the most common side. The traditional inductive type is composed of a core choke (eh*), which must be used with a starter to illuminate the fluorescent lamp. As shown in Fig. 1, there is a conventional assembly circuit of the actuator 10, the fluorescent lamp 20, the inductive ballast 3, and the plug 4A. When the power is turned on, the starter 1G is in a short-circuit state. At this time, the filaments at both ends of the fluorescent lamp 2G pass current, the temperature of the filament rises and emits electrons, and after the program, the starter 10 becomes an open circuit to achieve the purpose of pre-hearting (Prehearting). When the preheating is completed, the ballast will sense a high voltage so that the filament emits 1262745 hot electrons' and then illuminate the fluorescent tube 2G. Fluorescent lamp f2G_w - keeps open state, inductive...d 'starter 10 will: force, second time with long time (about 4_5 seconds), can't start immediately and Meng is used as a switch, so when starting The current is greater than the current at work... = desired =. 3. The bimetal as a switch metal is susceptible to external temperature and is iridized = fatigue and shortened life. 4. The large starting current at the start of the operation is easy to make the lamp due to: large, point 'minus the light official. 5. The traditional starter is often short of the end of the lamp life and the current causes the ballast to overheat and be damaged. In order to improve the above-mentioned conventional actuators, there has been an electronic reliance on the reference 6_u]. 2 is a block diagram of a conventional glory 4 electronic starter, which is composed of a rectifying circuit 110, a voltage detecting circuit 120, a preheating juice circuit 140 and an ignition circuit 130, and a terminal CN] is connected to CN2. At both ends of the fluorescent tube 20 tube. The rectifier circuit 11 is used to convert the AC power source into a DC power source for use with the electronic starter. The rectifier circuit 丨K) is divided into a half-wave type [Reference and full-wave [reference ι〇, ιι] 'Half-wave rectifier circuit has the advantages of low cost and high ignition voltage, but it will have electromagnetic at startup. Humming phenomenon. Therefore, the new electronic start-up uses a full-wave rectifier circuit to avoid electromagnetic hum. The voltage detecting circuit 12 in the electronic starter is used to measure the voltage across the fluorescent tube to determine whether or not electricity is applied to the fluorescent tube 2, and whether the fluorescent tube 20 is activated. When it is determined that a power source is applied to the lamp, the voltage detecting circuit (10) activates the preheating timer circuit 140 for controlling the filament heating of the fluorescent lamp tube 20 for a fixed time. Fluorescent: After the 笞20 is warmed up, the ignition circuit 130 operates to generate a high voltage, thereby illuminating the luminescent lamp. Finally, when the voltage detection circuit 12 knows that the power is off, it triggers the warm-up timer 140 to zero the warm-up timer. Generally, in order to save costs, the conventional preheating timing circuit is composed of a resistor 'electrical hybrid C' circuit as shown in Fig. 3 (4) to charge the capacitor (4) to a certain preset value. In other words, the electricity is used, so the following shortcomings are caused: 1. Conventional fluorescent lamp electronics: preheating timing circuit for each state of preheating time. The state-resistance capacitor cannot be charged to a certain preset value, so that the party The purpose is to shorten the life of the lamp (4). The 'preheating day' is fixed. 'It cannot change with the magnitude of the preheating current, so it often leads to excessive filament feeding and shortens the service life of the lamp. To this end, the present invention proposes a fluorescent lamp pre-acid start-up control relay for achieving the following two items: 丨·low voltage, the electronic starter can also operate normally; The current level of the light official filament is the best _ hot time, so that the glory lamp will not have the problem of insufficient preheating, the fluorescent tube can not be lit, and the fluorescent lamp will not be preheated. Lai's reading light makes the life of the cockroach pick, effectively reducing enthalpy, energy consumption and increasing lamp life. References: [1] STS Lee, HSH Chung, and SY Hui, UA novel electrode power profiler for dimmable ballasts using DC link voltage and switching frequency controls^ IEEE Trans. Power Electronics, vol. 19, iss. 3, pp. 847 -853, May 2004.

[2] T· F· Wu, Y· C. Wu, and Ζ· Y, Su, “Design considerations for single-stage electronic ballast with dimming featured IEEE Trans. Industrial Applications, vol. 37, iss. 5, pp. 1537-1543, Setp. 2001.

[3] G. C. Hsieh and C· H· Lin, “Harmonized strategy for breaking the striations in the fluorescent lamp/' IEEE Trans. Industrial Electronics, vol. 48, iss. 2, pp. 352-366, April 2001 .

[4] H. L. Cheng, C. S. Moo, and W. M. Chen, UA novel single-stage high-power-factor electronic ballast with symmetrical topology^ IEEE 1262745

Trans, Industrial Electronics, vol, 50, iss. 4, pp, 759-766, Aug, 2003 [5] CS Lin and CL Chen, "A novel single-stage push-pull electronic ballast with high input power factor,^ IEEE Trans. Industrial Electronics, vol. 48, iss. 4, pp. 770-776, Aug. 2001.

[6] K. I. Gyoten and N. Yoshikawa, ^Development of an electronic starter for fluorescent lamps^ Journal of IES. pp. 86-88, 1995.

[7] S· Yeo, DH Lee, and S. B. Song, “A simple electronic starter capable of end-of-life protection for fluorescent lamps, ^ Proc, IEEE Applied Power Electronics Conference and Exposition (APEC), vol. L, pp. 473-479, March 1999.

[8] Gu Zhenguo, “Republic of China Patent: Improvement of the Instant Starter of Fluorescent Lamps,,, Announcement Size: 360458, 1999/06/01

[9] Lu Zhaozheng, “Republic of China patents··Twilight Electronic Starter,,, Announcement Font Size: 215985, 1993/11/11 [10] Gu Zhenguo, “Republic of China Patent: Improvement of the electronic starter of fluorescent lamps, ,, Bulletin Size: 474549, 2002/09/11 [11] B. Marco, "US Patent: Electronic starter circuit for fluorescent lamp,,, Bulletin: US5616992, 1997/04/01 '

8 1262745 SUMMARY OF THE INVENTION The object of the present invention is to make an electronic start! I does not have the problem of insufficient preheating to illuminate the fluorescent tube at low voltage; another object of the present invention is to make the electronic female device at a high voltage. At the same time, there is no problem that the fluorescent tube has a face that is too short to reduce the fluorescence. - a fluorescent lamp preheating and starting control device, wherein the control device comprises a preheating time counting device, a preheating time judging device and a preheating current detecting device; wherein the preheating current device Is used to detect the preheating current of the fluorescent tube filament 'the preheating current data is sent to the preheating time judging device; the preheating time judging device' is for receiving the preheating current detection The pre-measurement measured by the device, and according to the size of the flow value, the most suitable for reading f preheating daily sales, ^ = lamp preheating time data and sent to - preheating daily sales timing device; The hot time timing device is used to receive the aforementioned service timing shut-off device to determine the most suitable lamp warm-up time. First, the preheating current _ device ς " first k official filament preheating current size ' «This preheating current data is sent to the pre - 埶 door is dead; then, the preheating time judging device according to the preheating current value The size determines the appropriate light official service, the most suitable for the pre-scale information money to a keeper timing device; finally, pre-emptive. Take the rhyme and daytime chronograph timing device. The most suitable lamp preheating includes: - 3 ΓΓ tender tender 嶋, Axisaki set system DC power supply === 峨 叙 ,, _ AC power supply. The hot day $ controller is located after the above-mentioned whole # output terminal 'used to detect the fluorescent tube: the road „, take the appropriate lamp preheating time, and control the fluorescent lamp pre-, after a pumping, Used to generate - high pressure, enter (four) in the "respective time controller and then point to the redundant light tube; where the preheating time controller package 1262745 preheating, breaking device and - preheating current detection boots preheating current data to send To the breaking device, is used to pick you up, paste preheating time judgment device; a preheating time judgment, and according to (4); ΓΓ thermal current (four) device measured preheating current value Ti · flow value Suitable for the light tube _ _ material and red _, pre = suitable for the future, the most device, is used to receive a ten, _ *, hot day alone timing device; a preheating time meter, and time 々 most ,: '1"~日尔 ij断装置Discriminate the most suitable lamp preheating J τ & Hai take the appropriate lamp pre-winding door, &a Mp;

The preheating current of the glory lamp filament is: this hundred first, the preheating current detecting device is prepared and judged, the device is installed, and the preheating current is sent to a preheating time meter. The lamp is tilted and sent to a preheating room. In the bean, ..., the time between the device and the timing device for the pre-heating of the lamp - a kind of circuit-wave full-wave rectifier circuit or a half-wave rectifier circuit. • μ and ', ★ light preheating and start control, the start control device is Baodi-pole, a second diode, a third diode and a fourth diode - Bridge full-wave rectification circuit; - micro-processing _ _ resistance composition - preheating:: the first transistor, a first - MOSFET, a second (four) ^ fourth packet resistance constitutes an ignition circuit. For example, in the application of the patent scope, the camp light power: start the 'rectifier circuit', which is located after the AC power input end, and is used to make the AC/claw private source into DC power for the electronic starter. Wherein, the preheating time controller is configured to detect the preheating current of the filament of the neon lamp after the end of the rectifying circuit wheel, and determine the most suitable lamp according to the magnitude of the preheating current value. Preheating time, and the fluorescent lamp is preheated for a suitable warm-up time. Among them, the ignition circuit is used to generate the high voltage after the preheating time controller, and then illuminate the fluorescent lamp camp. The microprocessor has a built-in timer, an analog-to-digital converter and an arithmetic arithmetic unit. Wherein, the built-in microprocessor and the analog digital converter and the first resistor constitute a pre-

(D 1262745 thermal current detecting device. Among them, the built-in timer of the microprocessor is used to realize the function of the preheating time counting device. The arithmetic logic unit built in the microprocessor is used to realize the preheating time ... - a kind of silk rhyme control method, which comprises the following steps: a. glory light = the preheating current of the filament; b. according to the magnitude of the preheating current value determines the suitable warming time of the lamp; c. Timing the most suitable lamp preheating time. A method for preheating and starting control of a fluorescent lamp, which comprises the following steps: a. short circuit at both ends of the lamp, so that the lamp relies on the brewing current; Tube __Thermal current is large according to the preheating current value, the most suitable lamp pre-scale; c. Timing the most suitable lamp preheating time; d. The lamp is open at both ends, electromagnetic ballast Inductive high voltage, and then illuminate the fluorescent tube. [Embodiment] As shown in the 4th, the flashlight of the present invention is a flashlight electric starter block diagram 'it is rectified Circuit „G, ignition device m, fluorescent tube preheat controller U0, and Sub-CN1 and (10) are connected at both ends of the fluorescent lamp 2. The camping lamp preheating controller 130 is composed of a warm-up time counting device (3), a warm-up time judging device 132 and a preheating current detecting device 丨33. The circuit cutting is used to turn the AC power into a f-current for the electronic start-up electronic circuit. The DC triggers the warm-up time determining device 132 to start the operation. First, the warm-up time determining device 132 receives the preheating device 133. The _thermal current value is tilted, and the magnitude of the preheating current value is determined to be out, which is suitable for the lamp warm-up time. Then, it is difficult to time the preheating time (3) to start counting the most suitable warm-up time 'in-situ count _ After the beam is reduced, the preheating time is set to (3) ^ trigger the ignition device' to illuminate the blast level. The fluorescent tube preheating control proposed by the present invention "b determines the suitable lamp according to the size of the preheated cake value. Preheating time, can effectively solve the problem that the technology is not enough to illuminate the fluorescent wire# and the fluorescent tube occurs 1262745 preheating to reduce the life of the fluorescent tube. As shown in Figure 5 A preferred embodiment of the invention is characterized in that Compact structure, good performance, can still work normally at low voltage, very commercial value. In Figure 5, diode D Bu D2, D3 and D4 form a bridge full-wave rectifier circuit 11〇; MOSFET Q2 and resistance state R1, illusion, R3 constitute an ignition device 12; microprocessor M1 and resistor R4 constitute the glory lamp preheat controller 13 of the present invention; wherein = resistor R4 and microprocessor The analog digital converter ADC built in Ml constitutes a preheating power detection device 134, and the timer 7lmer built in the processing state Ml is used to realize the function of the preheating time Ye Rishi' device 131; the microprocessor M1 The built-in arithmetic logic unit ALU is used to implement the warm-up time determining means 134; and the terminals (10) and (10) are connected to the fluorescent tube plus both ends. The working principle of the whole electronic starter is described as follows: When the power is turned on, the fluorescent tube 20 is not yet lit, and the fluorescent tube 20 is in an open state, so the commercial power 11〇ν is directly added to the electric & sub starter The terminals CN1 and CN2 pass through the rectifier circuit 11G to obtain a strange positive voltage. This voltage is processed and sent to the microprocessor ϋ M1 to start the microprocessor. The microprocessor M1 - starts to trigger the transistor Q1 to be turned off, and a voltage between the M 〇 SFET Q2 can be obtained to turn on the MOSFET Q2 to form a filament flowing through the fluorescent tube 2 () 0, the rectifier circuit 11 〇, M 〇 The circuit of SFETQ2, resistor R4, and the filament in the fluorescent tube 2〇 flow through the preheating current. The current flowing through the resistor R4 can be approximated by the current in the fluorescent tube* and the wire. According to Ohm's law, the voltage is proportional to the current, so the microprocessor MU draws the voltage value on the resistor R4, and this voltage is converted into digital data by the analog digital converter ADC of the microprocessor Mlxia. The inference of the digital data transmitted to the microprocessor's built-in arithmetic logic unit flows through the preheating current of the filament, and when the touch is mixed, the internal calculation is performed. Shout Time. When the daily rotation count is over, the trigger transistor QV turns off the MOSFET Q2 to generate a high-voltage single-trigger pulse to illuminate the fluorescent tube 1262745 20 °. This example has the following advantages: l Conventional fluorescent lamp The electronic starter often uses a resistor and a capacitor to make a preheating time of the preheating circuit. Therefore, when the mains abnormality drops too low, the capacitor cannot be charged to a certain preset value, and the inch is always warmed up. The purpose of lighting can not be completed, and the light in the lamp and the life of the lamp will be shortened. Then, the warm-up timing device in the fluorescent tube preheating controller 13 of the present invention is completed by referring to the timer inside the U processor M1, so the warm-up time is not affected by the mains abnormal IV or the low voltage. As apparent from the above, the electronic starter using the fluorescent tube preheating control of the present invention of 130 can operate correctly at a low voltage. The preheating timer circuit of the 2.3⁄4 fluorescent lamp electronic starter is often composed of a resistor and a capacitor. Because the values of the resistor and the capacitor are not easy to be accurate, the heating time cannot be accurate = the ideal value is reached, so the fluorescent lamp often occurs. If the heating time is too long or the heating time is insufficient, it will not only waste electricity but also shorten the service life of the fluorescent tube. Then, the preheating timing device (3) in the cut-and-tube preheating controller no of the present invention is completed by using a timer inside the microprocessor, and the error value is about a predetermined number of about 1 to 6 seconds, which is effective. The electricity cost is saved, and the service life of the lamp is extended. After the ray is used to make a 40W fluorescent tube, the wire preheating current will be proportional to the magnitude of the voltage supplied to the mains: ^ 95V, the resistance is on the _ waveform when the filament is warmed up. For the city, the city power 1 Qing and the city power blue, filament pre-figure and brother 8 map, respectively, Figure 7, Figure 7 and Figure 8 can clearly see the voltage waveform on the second. Since the sixth current also rises in a proportional manner, the resistor R4 ′ : rises, the filament warms up and rises. On the other hand, when the mains is dependent on Lai and the preheating current drops, the power of the resistor R4 can be used. ^=The preheating current will also be proportional to the Mia, which will cry according to the resistance. ~ The size of the preheating current. The slightest is mixed and the best warm-up time is calculated. Figure 9 1262745 is the phase preheating current of the mains and the preheating time, and then the preheating time of the filament is _ 円 市 = = = = = = = = = = = = = = = = = = = = = = In the lower city electricity phase, the lamp 贞 is longer when the utility power is 95V. The third 丨 η η 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图 图The graph can be: Γ and voltage, the warm-up time is about 〇·4 seconds. From the first pass, but the sentence, 疋, the surface _ will change with the electric voltage, the fluorescence of the present invention, the time will vary with the magnitude of the preheat current. Therefore, it can be known from the experiment that the ir preheating time control (4) can be based on the preheating current of the filament of the material lamp, and the fluorescing tube will not occur. Occurred in the role of short-term use of p, 17, effective in reducing energy consumption and increasing lamp life. Further, as can be seen from Fig. 10, the electronic starter of the present invention can normally illuminate the lamp when the mains is too low. 1262745 [Simple description of the drawing] Fig. 1 is a conventional fluorescent lamp, ballast and starter assembly circuit. Fig. 2 is a schematic diagram of a conventional electronic starter block. Fig. 3 is a schematic diagram of a conventional preheating timing circuit. FIG. 5 is a block diagram of a preferred embodiment of the present invention. FIG. 6 is a diagram showing the waveform of the resistor R4 when the filament is preheated when the mains is lowered to 95 V. The seventh diagram of the present invention is a filament preheating at a normal power supply of 110 V. The waveform of the thermal resistance R4 is shown in Fig. 8. The waveform of the resistor R4 when the filament is preheated when the commercial power is raised to 130V. FIG. 9 is a relative diagram of the mains voltage and the warm-up time. FIG. 10 is a diagram showing that the utility model drops to 95V in the commercial power supply. The measured results are shown in Figure 11 for the measured results of the invention under normal 110V power supply. The 12th figure shows the measured results of the invention in the market power up to 130V.

5 1262745 [Description of main component symbols] 10.. Starter 20. · Fluorescent lamp 30·,. Inductive stability is 40... Plug 110... Rectifier circuit 120... Ignition device Π 0... Fluorescent lamp warm-up time controller • 131... Warm-up time timer device 132.. Pre Thermal time judging device 133.. Preheating current detecting means 141, 142, R Bu R2, R3, R4. " Resistor 143.. Capacitance

Dl, D2, D3, D4.··II

Q1...transistor Q2...MOSFET

16 8

Claims (1)

1262745 Patent application scope ··1, a type of fluorescent lamp preheating ( ( (10), and the time, the most suitable lamp pre-determination (9) is most suitable for the lamp J-preheating time chronograph, _,, 7 preheating time timing device; combined with the lamp management time, and the judging device determines the first = thermal current detecting device; preheating, preheating the package flow to a pre-execution, pre- According to the size of the preheating current value, the value of the preheating current is set to be ''then' when preheating_breaking the device according to the heat time data and sending it to 1 heat === pre-, the most Suitable for the lamp to set the time for the most suitable lamp. You set '(four), lag time to install two ϊ ” light preheating and start control device, which includes: electric === flow power input end, then the axis will be integrated into a DC lamp ί lamp == flow: t In the ΐ ΐ flow circuit, after the end, 'for the fine work light ^ L sub depending on the magnitude of the preheating current value determines the suspension of the second two: when, and control the glory preheating a section of the most suitable preheating Time; and the glory light ί is located after the preheating time controller is used to generate - high voltage, Jinshi Shishen = patent range, item 2, which has both the fluorescent lamp preheating and starting control device, among which The thermal time controller comprises a warm-up time counting device, a warm-up time determining device and a pre-heating current detecting device; wherein the preheating current detecting device is configured to detect the preheating current of the fluorescent lamp filament The preheating current data is sent to a preheating time judging device; a preheating time judging device is configured to receive the pre-heating current detecting device to measure the pre-heating current value data, and according to the pre-heating The magnitude of the thermal current value... time 'this is best The lamp preheating time data is sent to: take the 1^ lamp official pre-cooking and preheating time timing device, which is used to receive the aforementioned lying time meter, "set; the lamp preheating time, and time the The most suitable lamp = pill = device determines the optimum. Therefore, when the preheating current detecting device detects the fluorescent lamp t and sends the preheating current data to the preheating time f of the preheating time, the device is based on The value of the preheating current value determines the most suitable for the second: = the light bulb pre-study material #...$ and g pre-, 4%, the best, the heart, shipped to a preheating time timing device : Finally, _ two things 1 set the time for the most suitable lamp preheating time. Take the stupid pre-heating lamp and pre-heating control device as described in item 4·2, suitable for 5:2: The wave rectifying circuit or the half-wave rectifying circuit is a type of device, and the f-lighting surface and the initiating relay include: a first diode, a second diode, and a second-K^ bridge. Full-wave rectification circuit; the second two-pole body and one young four-diode body - one = the first - the resistance constitutes - the preheating time controller; the first transistor, a first MOSFF T ^ _ resistor constitutes - ignition circuit. Dior two resistors, a third resistor and a fourth 6 · ΐ ί ΐ ΐ ΐ ΐ 第 兼 兼 萤 萤 萤 萤 萤 萤 萤 萤 萤 萤 萤 萤 萤 萤 萤After the power input terminal is used to make the AC power supply into a direct electromechanical electronic starter. 7* 5 . * Controlled by $2, which is located at the output of the rectifier circuit and used to detect the flasher. The temperature of the preheater of the wire is determined according to the magnitude of the preheating current value, and & preheating between the day and the control of the fluorescent lamp pre-heating - the most suitable preheating :?2 yoke circumference item 5 has both a fluorescent lamp preheating and starting control device, and the 'black fire circuit' is located behind the aforementioned warm-up time controller for generating a high voltage, thereby illuminating the fluorescent light Light tube. In the 18 8 1262745, the microprocessor has a built-in S-timer, an analog-to-digital converter and an arithmetic arithmetic. The logic οα is early. 10. If you apply for a fluorescent lamp surface device as described in item 9 of the Wei Wei®, the microprocessor has a built-in analog digital converter and a first resistor to form a preheating current detecting device. w]]] The fluorescent lamp preheating and starting control device as described in claim 9 of the patent application, wherein the built-in timer of the microprocessor is used to realize the function of the preheating time counting device. 12. The fluorescent lamp preheating and starting control device as described in claim 9 of the patent application, wherein the microprocessor-built heterogeneous logic unit is used to implement the warm-up time judging device. 13·—A method for combining the fluorescent lamp preheating control, comprising the following steps: a• detecting the preheating current of the fluorescent lamp filament; b· determining the most suitable according to the magnitude of the preheating current value Lamp preheating time; c• Timing the most suitable lamp preheating time. 14. A method for preheating and starting control of a fluorescent lamp, comprising the following steps: a: short-circuiting the two ends of the lamp to cause the filament to flow through the preheating current; b• detecting the preheating current of the filament of the fluorescent lamp b. According to the magnitude of the preheating current value, determine the most suitable lamp preheating time; c• time the most suitable lamp preheating time; d• the lamp is open at both ends, the electromagnetic ballast senses a high voltage And then illuminate the fluorescent tube.