i am quite new in electronics department and so have a very little knowledge about it...ok so i am going to set up a 555 oscillator.....i have the 555 timer chip, a solderless breadboard and resistors ...
I have tried a while to understand how the 555 chip is built, I opened the datasheet of TI available here : http://www.ti.com/lit/ds/symlink/lm555.pdf anyway this is the scematic from the datasheet ...
MightyOhm has designed a geiger counter which is here. I am not very clear but I think he is using the 555 timer as an oscillator in the high voltage power supply section. I've attached his schematic ...