3SUP1_SUP_SUB2_SUB_DIGIT_DVM

Published:2009/7/15 4:13:00 Author:Jessie | From:SeekIC

Combination of National LF11300 dual-slope analog building block and MM74C928 CMOS 31/2-decade counter with 7-segment outputs gives automatic-zeroing automatic-polarity 31/2-digit digital voltmeter. Counter drives LED display with multiplexed 7-segment information under control of internal free-running oscillator. Interface circuits provide nonoverlapping control signals to LF11300 for polarity determination and offset correction for every conversion cycle. Analog circuit draws 1.5 mA from each 12.5-V battery. Digital circuit draws about 40 mA from 6-V supply.- CMOS Databook, National Semiconductor, Santa Clara, CA, 1977, p 5-36-5-37.



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