Long cycle on / off multivibrator

Published:2011/5/17 4:02:00 Author:Ecco | Keyword: Long cycle , on , / off , multivibrator | From:SeekIC

The multivibrator composed of 555 timer IC can adjust the frequency and duty cycle independently, but if the on / off cycle is very long, it needs a large capacity capacitor. The circuit shown as the chart can adjust the on / off cycle flexibly without using large capacitors, and the longest period can reach several hours. It uses CD4020 14-stage binary counter to count the output frequency, the two output terminals Ql4 of CD4020 will rise and fall to connect to the edges Rl and R2, it can output separate off-cycle and on-cycle. The output end Q1 can be used to indicate the continuous cycle. If R2 = 100k time, Ton ≈ 5 minutes; if Rl = 1M time, Toff ≈ 50 minutes.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Signal_Processing/Oscillator_Circuit/Long_cycle_on___off_multivibrator.html

Print this Page | Comments | Reading(3)