BATTERY_BACKUP_1

Published:2009/7/1 3:57:00 Author:May | From:SeekIC

Four nickel-cadmium batteries connected in series provide automatic backup for 5-V supply of digital clock. Under normal AC line operation, battery is continually being recharged with half-wave rectified and unfiltered supply that allows internal chemical reactions to settle between pulses of charging energy. R1 is chosen to make average charging current about 5% of battery rating.-D. Ald-ridge and A. Mouton, Industrial Clock/Time( Featuring Back-Up Power Supply Operation, Motorola, Phoenix, AZ, 1974, AN-718A, p 7.



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