This circuit and project demonstrates the application of 555 to generate negative supply. The negative supply produced is about 3 volts lesser than the applied [[wysiwyg_imageupload::]]voltage due to various losses. At times the circuit requires both negative and positive supply, which is not available in the batteries. IC555 includes two comparators, one RS flip-flop and other few discrete components like transistors, resistors etc. The biasing voltage (Vcc) is divided in three parts through voltage divider using same value of resistors R. from these 1/3 Vcc is given to non inverting terminal of trigger comparator and 2/3 Vcc is given to inverting terminal of threshold comparator. The outputs of both comparators are given to R and S inputs of flip-flop. The Q’ output is actual output of IC and Q output drives. In this project, 555 work in astable mode and produces a frequency of about 663 hertz.