Time for some back up, I'm stumped.
I am building a two stage timer to trigger a camera refresh and shutter. I used two 555's cause my simulater doesn't offer a 556. The output of the first stage will trigger a opto isolator for the camera wake up pulse, while the high output charges the second stage delay cap/resistor(C6,R10). When the output on the first stage goes low, The second stage trigger voltage decays to <1/3 vcc, the second stage pulse is triggered to another opto isolater driving the shutter. Here's the rub; When either stage is low, a 460mV ripple appears on the outputs. This might not happen in real life, or it might. I tried tying the resets to ground with 100pf caps, no good. I tried the same w/ the outputs, no good. I lowered the cap/ resister values down to shorten the times so that my oscilloscope will not time out. The real values will reflect the delays needed. The ripple is killing my simulators ability to display all the delays. (The ripple is at 500Khz in case that helps...) I also tried tying the output ot the first stage to the inputs of the second, but that was worse w/ no triggering at all. Any suggestions?? Thanks in advance!! Both stages work separate, just don't play well together!!!
I am building a two stage timer to trigger a camera refresh and shutter. I used two 555's cause my simulater doesn't offer a 556. The output of the first stage will trigger a opto isolator for the camera wake up pulse, while the high output charges the second stage delay cap/resistor(C6,R10). When the output on the first stage goes low, The second stage trigger voltage decays to <1/3 vcc, the second stage pulse is triggered to another opto isolater driving the shutter. Here's the rub; When either stage is low, a 460mV ripple appears on the outputs. This might not happen in real life, or it might. I tried tying the resets to ground with 100pf caps, no good. I tried the same w/ the outputs, no good. I lowered the cap/ resister values down to shorten the times so that my oscilloscope will not time out. The real values will reflect the delays needed. The ripple is killing my simulators ability to display all the delays. (The ripple is at 500Khz in case that helps...) I also tried tying the output ot the first stage to the inputs of the second, but that was worse w/ no triggering at all. Any suggestions?? Thanks in advance!! Both stages work separate, just don't play well together!!!
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