555 Timer

What happens to the output voltage when the 555 timer supplies higher
current? how good is the program multisim? Would it be worth the
investment?

 

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 www.linear.com. It's free.

 

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:

http://www.national.com/pf/LM/LM555.html#Datasheet

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