555 Timer

My guess is that the only effect that drawing more current from the output of a 555 will have is that it'll heat it up. However, the timing will probably not be affected; the timing is based on a comparison between a three-way internal resistive divider, and the trigger and threshold inputs. That won't change much when the thing heats up.

As to the simulator, I'd try LTSpice first, from

The output voltage droops (Vcc - Vout gets larger).

Hi, smokie. As current sourced or sunk through the output transistors of the 555 increases, more voltage is dropped across those transistors. Look at page 5 of the datasheet for graphs of output voltage vs. output current:

It's usually a good idea to look at the datasheet.

Newbies in electronics need some background and basic knowledge before they can make good use of simulation programs. You might be better off downloading LTSpice as mentioned in another post, then taking the money and enrolling in a summer course at the local junior college.

Good luck Chris