is this a multism problem or a circuit problem

[adown]

I couldn't figure out the schmitt trigger circuit so I am usin a 556 timer. I have simulated the circuit in multism and it sequences at the speed I want but when I open the switch the circuit stops at that point an the led's that were lit stay lit. Is this just the simulator or do I need to do something different to have them shut off when I open the circuit. Thanks

 

[ericgibbs]

I couldn't figure out the schmitt trigger circuit so I am usin a 556 timer. I have simulated the circuit in multism and it sequences at the speed I want but when I open the switch the circuit stops at that point an the led's that were lit stay lit. Is this just the simulator or do I need to do something different to have them shut off when I open the circuit. Thanks

hi,
In what sequence are you closing/opening the switches.?

If you switch power off the to 556, the 4015 inputs may give problems neither high or low.??

This wouldnt show up in a sim.

EDIT:
I would try say 2.2K resistors on all the connections from the 556's to the 4015, between the pins and 0V, maybe enough to give a logical zero.