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The Journal of the Royal Institute of Thailand Vol. 33 No. 1 Jan.-Mar. 2008 122 °‘ µµ‘ °√√¡ª√–°“» ºŸâ π‘ æπ∏å ¢Õ¢Õ∫§ÿ ≥ ¥√.Õ√√≥æ ≈‘È ¡ ’ ¡“√— µπå ∫— ≥±‘ µª√‘ ≠≠“‡Õ° Àâ Õߪؑ ∫— µ‘ °“√«‘ ®— ¬‰øøÑ “·√ß Ÿ ß ¿“§ «‘ ™“«‘ »«°√√¡‰øøÑ “ §≥–«‘ »«°√√¡- »“ µ√å ®ÿ Ó≈ß°√≥å ¡À“«‘ ∑¬“≈— ¬ ∑’Ë ‰¥â ™à «¬‡À≈◊ Õ„π°“√∫— π∑÷ °√Ÿ ª§≈◊Ë πª√‘ ¡“≥ ‰øøÑ “¢Õß«ß®√ÕÕ ´‘ ≈‡≈‡µÕ√å „π ∫∑§«“¡π’È Abstract Current-feedback Oscillators for Lighting a Fluorescent Lamp by a Battery Mongkol Dejnakarintra Fellow of the Academy of Science, The Royal Institute, Thailand This article presents two current-feedback oscillators for lighting a 18-W fluorescent lamp by a battery. The circuits include one configuration using a bipolar transistor and the other using a MOS transistor. With the circuit components as presented, both circuits give a better performance than those of the voltage-feedback oscillators using the same principal components. Particularly, the current-feedback oscillator that uses a MOS transistor gives an electrical efficiency in the 58-73 percent range, whereas the voltage-feedback oscillators using bipolar transistors yield an electrical efficiency lower than 50 percent. Key words : Oscillator, current feedback, fluorescent lamp ‡Õ° “√Õâ “ßÕ‘ ß [Ò] Nowicki, J. R., Power Supplies for Elec- tric Equipment, Vols. 1-2, Rectifiers, In- verters and Converters, Leonard Hill Books, London, Ò˘˜Û. [Ú] Õ√√≥æ æ’ √™“µ‘ . · ߉øªî °π‘ °. HOBBY ELECTRONICS 81. °∑¡. : ´’ ‡ÕÁ ¥¬Ÿ ‡§™—Ë π, 2541, Àπâ “ 25-28. [Û] Millman, J., and H. Taub, Pulse, Digital and Switching Waveforms, McGraw-Hill, ÕÕ ´‘ ≈‡≈‡µÕ√å ·∫∫ªÑ Õπ°≈— ∫°√–· ‡æ◊Ë Õ°“√®ÿ ¥À≈Õ¥«“«· ߥ⠫¬·∫µ‡µÕ√’Ë N.Y., 1965, pp. 597-621. [Ù] Roddam, T., Transistor Inverters and Converters, D. Van Nostrand Co., Princeton, New Jersey, Ò˘ˆÛ, pp. 93- 115. [ı] High Frequency Electronic Lighting Sys- tem, pamphlet No. 1024-948-00251- 4/84, Philips Lighting Division, Eindhoven, The Netherlands, 1984, p. 3.