Published:2009/6/25 21:02:00 Author:Jessie | From:SeekIC
Circuit NotesIn the 556 timer, the timing is a function of the charging rate of the external capacitor. For long time delays, expensive capacitors with extremely low leakage are required. The prac-ticality of the components involved limits the time between pulses to something in the neighborhood of 10 minutes. To achieve longer time periods, both halves of a dual timer may be connected in tandem with a Divide-by ' net-work in between the first timer section oper-ates in an oscillatory mode with a period of 1/fo. This signal is then applied to a Divide-by-N network to give an output with the period of N/fo. This can then be used to trigger the second half of the 556. The total time delay is now a function of N and fo.
Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Basic_Circuit/Digital_Circuit/LONG_TIME_DELAY.html
Print this Page | Comments | Reading(3)
Code: