The ctl pin usually has a capacitor attached in most schematics. By applying a voltage to this pin you can change the duty cycle. As far as I can tell, the voltage needs to be at sufficiently low impedance so it has an effect on the internal workings.
The ctl pin usually has a capacitor attached in most schematics. By applying a voltage to this pin you can change the duty cycle. As far as I can tell, the voltage needs to be at sufficiently low impedance so it has an effect on the internal workings.
???You actually have asked in a forum what to do with pin 4 and pin 5 of a 555??? You need to be fast-tracked to the finalists of Engineer of the Year if such a prize exists. It's well-intentioned leg-pulling, not trolling, friend.
There are loads of online datasheets (mainly older datasheets for the 555) and application notes with good explanations, a variety of standard timer IC circuits used/in use. Sometimes it's worth searching the Internet yourself. Here are two. I can add others if you're interested and find the required time to read up on what you're doing before doing it .