What can be used to provide -5V potential to a circuit?
What can be used to provide -(minus) 5 volts in the circuit diagram given in the link below?


I have used the bootstrap circuit shown in the schematic below  and works pretty well (top section).



It uses 74HC04, the first two gates are used to generate an oscillation and then four gates are connected in parallel as an output stage to provide more output current to the bootstrap circuit (diodes/capacitors section).



There is also the circuit shown in the datasheet of ICL7107