A dual voltage power supply circuit is shown below. It can be any voltage depending on the requirements of the dual voltage power supply you are working with. Some IC chips only require a single supply and some IC chips can be used with both. Always check the specifications on the particular chip to see the battery requirements, single or dual.
The diagram below shows the correct hookup for a dual voltage 9 volt power supply circuit.
Use the same hookup for other voltages on any IC chips that require a dual voltage power supply, other than the 9 volt example shown. This dual voltage power circuit diagram would be the standard hookup for any devices and the exact diagram for all chip circuits requiring a dual voltage power supply.