His circuit holds the voltage at Vcc/3 so that the 1st pulse will be accurate. If you just pull it to ground the 1st pulse will be long. You are using very large values so sometimes leakage current can be a problem. I'm thinking you must be using a CMOS 555? Like LMC555? You can fix your floating input by adding a resistor - say 47k from base to ground on the first transistor.
I understand that he said it would hold it to 1/3 while reset is held down. But I don't really understand how that works with the mix of resistors and npn and pnp transistors on that left side circuit. Maybe it is too difficult to explain but I was hoping somebody might find that not too difficult.
In my case maybe I don't even really need to worry about that complexity either--not sure. Because I really don't need consistent after pulses, I really just want to discharge the time cap and start over. Too bad "reset" doesn't actually do just that. Basically I have another circuit that I want to sleep for 6 min so I was thinking to use the 555 as a monostable. The initial pulse of 6 min would keep the other circuit off and then turn it on using the out pulse change after six minutes over a low current relay. At first I thought mosfet but I need to keep the ground of the other circuit the same as the first and it seemed to be more trouble to do a high side mosfet.
[You are using very large values so sometimes leakage current can be a problem. ]
Any ways around that?
[I'm thinking you must be using a CMOS 555? Like LM
C555?]
Yea NTE955MC does that have anything to do with extra leakage? any suggestions there? also using a 9014 for the npn transistor... was what was lying around.
[You can fix your floating input by adding a resistor - say 47k from base to ground on the first transistor.]
So in my attached picture, I have a switch attached from +volts to a resistor attached to the base of the npn. This was to simulate the other circuit resetting the time cap.
And in the simulator it worked fine with the high values 3Mohm and even on the breadboard from what I remember it seemed to work and reset. but when actually soldered all together it doesn't seem to work the same. I see voltage over the time resistors dropping and then they get to that almost trigger point and then start going backward. like the cap starts to discharge a bit through the npn. without the npn in the circuit it works fine.
One other thing to note is that it would be an arduino digital pin that I was using as the input to the reset and that it would look like ground part of the time vs an open like the switch seems to be. so I had just put in a 1k between arduino out pin and the npn base.