LED_DIE

Published:2009/7/7 22:54:00 Author:May | From:SeekIC

When positive bias on input of IC1D number displayed. Number can be between 1 NAND gate is puiied to ground by skin resistance of finger, D flip-flop IC2A connected as mono is triggered. Pin 1 goes high for about 2 s, making IC4. latch outputs of counter IC3 andunblank LED display. Randomtime that fingeris on touch plate determines randomness of number displayed. Number can be between 1 and9, between 1 and 6 for die,between 1 and2 to representheads or tailsChange BCDof jam inputs of IC3 to highest random number desired .Values shown are for 4.5-V supply and dispiay current of 10 mA PER SEGMENT. LEDisblanked until plateis touched Standby current drain of 10 μA on three AA alkaline cellsis so low that ON/OFF switch is unnecessary．－C,Cullings,Electronic Die Uses Touchplate and 7Segment LED Disρlay,EDN Magazine,May 20,1975、p70 and 72.



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