The difference between using one 555 timer and a 556 timer for PWM control

[JedOs86]

I have seen different site using 556 set up as one timer in astable
controlling a second timer in monostable mode. Other sites show PWM by
using only one 555 timer set up in astable mode. I would really rather
use only one 555 timer, but what is the upside to using a setup with a
556 timer?

 

[gogo2520]

Hello JedOs86
    The 556 timer is two 555's in one ic chip. In the 556 package you can use just one of the timers if you want.
                        Hope that helps
                                  gogo

 

[indulis]

One thing that will happen when you use a single 555 as a PWM is that the switching frequency will move around (a lot) when you vary the voltage on the control voltage pin.