LTSpiceIV, available from Linear Technology, allows you to construct moderately complex 555 driven circuits including common components such as capacitors, resistors, diodes, FETs, and more.

As said earlier how long the pulse stays high, how long the pulse stays low and the frequency of the pulse can be calculated using the value of components R1,R2 and C1 shown on the circuit diagram ...

If you’re not familiar with the 555 ... other circuits if you need something special, or just want to play around in analog-land for a change. Do these modern takes on the classic timer IC ...

In this project we build a boost converter circuit using a 555 timer IC. Boost converter is a non-isolated type of switch… A Simple 555 Timer based Buck Regulator for LED Dimmers and DC Motor Speed ...