LAMTERN_BATTERY_EXTENDER_

Published:2009/7/13 4:19:00 Author:May | From:SeekIC

Life of lanternbattery can be tripled without reducing light by chopping current while doubling voltage at 50% duty factor. 6-V lamp is connected across chopped 12-V supply built around 4011 CMOS quad NAND gate. First two gates form chopping oscillator, while third serves as interface to any NPN high-gain power transistor. If lamp draws more than 1 A, add fourth gate as shown in dashed lines. If gate is not used, tie its input Ieads to pin 14 of IC. Duty cycle is varied with 1-megohm pot; set at midrange before ap-plying power, then adjust for normal lamp bril-liance.-J. A. Sandler, 9 Easy to Build Projects under $9, Modem Electronics, July 1978, p 53-56.



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