Help with delaying a signal

Discussion in 'The Projects Forum' started by bgosseli, Apr 23, 2011.

  1. bgosseli

    Thread Starter New Member

    Apr 23, 2011
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    0
    I have a NE555N IC producing a square wave signal with a frequency of about .333 Hz. I have it set up to be high (5 volts) for 2.9799 seconds and low (ground) for .0153 seconds. What I'm using the signal to set a latch on a 4511 IC to hold a value that a 7490 IC has counted to. My problem is that i'm also trying to use this signal coming from the NE555N after being inverted to send a reset signal to the 7490 IC to start counting over again. So i have the signal going to the 4511 to set the latches before the signal (inverted) goes to the 7490 to reset the counter. However i can't get enough delay in the signal going o the 7490 so that the counter isn't reset before the latches are set. If someone could help me with a way to achieve this delay that would be great. Thanks so much!

    See my problem is i can't use a RC filter because the spike is so small, but I don't know another way to do it.. =/ Any help would be greatly appreciated

    I need a delay of roughly .02 seconds = 20 ms
     
    Last edited by a moderator: Apr 25, 2011
  2. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    2,574
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    Please post a schematic of your circuit.

    Ken
     
  3. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,175
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    Ken , please holler if I put my foot in "it". Might try using 555 out as latch, inverted output is then neg. differentiated pulse with a .01 μF & 10K to pin 2 of another 555, set as OS with short output pulse as a reset You only need a 50 ns delay perSignetics. Mixed IC familys gives me hives.
     
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