I have attached two files of the 4047B that I am using as an astable like that shown in the second file. From the data, it appears to me that I can use pins 4 or 5 to gate the oscillator with either a 0 or 1 input to trigger. What I want to do is to burst fire it for the duration of a gate pulse, either logic 1 or 0 with appropriate switching. Free run is also enabled via these two pins.
The problem I am having is that it does not matter whether both are level 1 or 0 or one of them is 1 and the other 0, it free runs all the time. If on power on,it does show no output, as soon as a 1 or 0 is applied to the appropriate input, it will not stop again no matter what level either pin is at. I have tried pull up/down resistors with no change.
Wiring them as monostables works fine every time.
I don't think it is faulty ic's as I have 5 new from R.S, and10 others from different sources and they all do the same.
Any help would be appreciated.

 

From the data, it appears to me that I can use pins 4 or 5 to gate the oscillator with either a 0 or 1 input to trigger.

That will work if 6 connects to VDD and 8 Connects to VSS.

 

That will work if 6 connects to VDD and 8 Connects to VSS.

That is how I have it I will do a quick sketch of how i'm switching it.

 

The LTspice simulation seems to work.
Is this the circuit you are using?

 

Here is just a quick scribble of the actual circuit.

 

The LTspice simulation seems to work.
Is this the circuit you are using?

View attachment 154784

Similar except I am trying to select either a 1 or 0 to trigger.

 

Similar except I am trying to select either a 1 or 0 to trigger.

The Gate input is shown as floating.
What is it connected to?
Are you certain the switch is wired as shown?
Measure the signal at the 4047 inputs while observing the output.
Try switching just one input, as in the simulation.

 

The Gate input is shown as floating.
What is it connected to?
Are you certain the switch is wired as shown?
Measure the signal at the 4047 inputs while observing the output.
Try switching just one input, as in the simulation.

The idea is that "normal" operation is free running, but with the option to switch off free run and depending on use, either trigger it with a selectable hi input or a low input from an external source.

 

The idea is that "normal" operation is free running, but with the option to switch off free run and depending on use, either trigger it with a selectable hi input or a low input from an external source.

Edit,
yes I tried one input at a time, each will either start oscillation if it is off, or it is already free running. once started, cannot gate off. Even with the switch removed and wiring directly it is the same.

 

Edit,
yes I tried one input at a time, each will either start oscillation if it is off, or it is already free running. once started, cannot gate off. Even with the switch removed and wiring directly it is the same.

Then I don't understand why it's not working.

 

Then I don't understand why it's not working.

Unfortunately, neither do I. I will build just the oscillator on a bread board again and post some pics of the different configurations and results on the 'scope.
My brain is fried at the moment, so going fishing tomorrow and will have another crack at it on friday. Thanks for the help

 

I think I've solved it. In my original circuit it was running at around 15 kHz, I built just the oscillator on a separate bread board with the same value components and it did the same thing.
I changed R & C so that is was running at 500 Hz and it worked properly. It looks like I was getting capacitive? coupling from the breadboard tracks at the higher frequency, self triggering it.
Anyway, thanks for the help, I was beginning to think I had made some major error in design.