Wide-range Digital Capacity Measuring Instrument Circuit (NE555, CD4017, MC14553B)

Published:2011/8/10 8:17:00 Author:Felicity | Keyword: Wide-range, Digital, Capacity Measuring Instrument | From:SeekIC

The pulser is the multivibrator consists of IC1(556) and R1,R2,C1(R3,R4,C2), and the oscillation frequency is 1.44/(R1+2R2)C1，or f2=1.44／(R3+2R4)C2. The advancing edge of the pulse output by pin 9 make the output terminal of D flip-flop IC2(CD4013) generate low voltage that put on the enable terminal (EN terminal) of the counter IC4(CD4071) to make it count. The pulse output by pin 5 control the DIS terminal of the 3 bit BCD counting circuit IC5 (MC14553B) The test capacitor capacity-frequency transform circuit consists of R7, R8, and IC3 (555) and the test capacitor Cx. It transforms the capacity of Cx into oscillation pulse pending to test as the counting clock onto IC4.



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